Most of the questions below refer to the article: Good sleep for good learning
For questions about polyphasic sleep, see a separate FAQ: The myths of polyphasic sleep. See also the body of this file for more answers
Why do we sleep?
Question:
Why do people fall asleep?
Answer:
If you ask about the purpose of sleep: we fall asleep for the brain to get a chance to restructure memories stored during the day and associate these with previously learned things.
If you ask about the mechanism of falling asleep: it is not entirely understood. Some parts of your brain work by regularly stimulating and inhibiting each other. This produces a daily cycle of activity. Some structures are responsible for inhibiting those responsible for arousal. You get drowsy and the brain goes into a different mode of action: optimizing memory storage. After the work is done, your arousal center gets stimulated again and "get up and go" hormones enter the bloodstream. You are ready for a new day. For more details see Physiology of sleep section in Good sleep for good learning
Question:
I sleep seven hours per day and wake up with an alarm clock. I read
that
using the alarm clock may negatively affect learning. Is it true?
Answer:
There is a significant body of evidence that the you will get
the best results in
learning if you get a full night of natural sleep. Many individuals
need
eight or more hours of sleep. It is difficult to predict how damaging
the alarm
clock can be in your case. It will mostly depend on how much sleep your
body
actually needs
Question:
Why does this site not mention learning in the relaxed state?
What is your
opinion about alpha waves in learning? Do you recommend products like
BrainWave
Generator, Hemi-Sync, Holosync or Polish Sita biofeedback?
Answer:
We do realize that the proper cognitive environment is
paramount for
learning. However, for clarity we use the term concentration
instead of
an all-inclusive relaxation. It is highly
recommended that you maximize
your concentration by taking into account the following factors:
The concept of relaxation is often associated with alpha wave learning which has attracted lots of companies that are more interested in their bottom line than their customers actual success in learning. EEG measurements can be used to predicate on the current state of the brain as much as you can predicate on the bustling social life of a major city by scanning the surrounding electromagnetic field. The usefulness of alpha wave scanning in learning can be compared to the usefulness of electromagnetic field scanning in trying to understand human activities in a city. You need to focus on the causes rather than the symptoms. Alpha waves appear primarily in the absence of visual processing and other intense mental processes. This is why they cannot dogmatically be considered as a desired learning state. After all, the drowsy alpha state that precedes falling asleep is exactly the worst moment for learning during your day.
In evaluating the "relaxation products" you need to differentiate between the relaxation effect and the actual learning effect. The number of companies producing false claims in this field is astounding. It is very easy to fall for a simple solution to a learning problem (e.g. get 10Hz binaural beat difference and your learning problem will go away for life, and perhaps your sex drive will improve at the same time, you will sleep better and you will look younger). The "easy learning" bait explains why false claims related to "learning in relaxation" are so hard to extinguish.
At the same time, if you need to cope with stress or insomnia, many products in the field may have a legitimate application. Customers of the Polish Sita system jokingly claim that the company would do better if they marketed their product as a napping system. A worthy application on its own. If you know of relaxation products with legitimate claims and proven results, please let us know. We will gladly write about the subject or provide links from this site
Question:
It is well known that people can be divided into late sleepers, owls,
and
early sleepers, larks. Has there been any research to indicate what
sleeping
type has better memory?
Answer:
The conviction that people are set to be either
larks or owls
is wrong. Most owls would claim it is virtually impossible to shift to
earlier
hours of sleep while larks just cannot keep their eyes open late in
the
evening. However, the reason for this differentiation is largely dependent on the
lifestyle. The stereotype is reinforced by the fact that it is indeed
very
difficult to shift the sleeping rhythm even by a few hours. If you try
to force
an owl to start getting up at 5 am, you will expose him or her to immense
mental and
physical torture that may quickly result in serious health
consequences!
However, with the right approach, an owl can gradually be shifted into
an early
riser mode! The shift must
be gradual as no magic
force can instantly
override the body's internal clock. The main reason why owls are owls
is that
they tend to excitedly spend their time over a book, movie, or computer
game
till early hours of the morning. They enjoy the quiet of the night when
they can
pursue their passion. Subconsciously, they try to get as much of the
night time
for their pursuits as possible. Were it not for school obligations,
family or a
job, owls might easily shift to going to sleep at sunrise or later.
This is why
an owl will find it easy to go to sleep later and later, while it will
be nearly
impossible to gradually shift the sleeping rhythm in the opposite
direction (e.g. 20-30 minutes earlier each day). Owls may have a longer
clock period or be less sensitive to resetting signals, but they
can adopt a farmer's lifestyle and become larks. If an owl
goes to sleep 1 hour later each
day,
soon it will cycle to sleep through the day and finally start getting
up as
early as 1-2 am. An owl can comfortably stick to such a cycle for quite
long
until its natural tendency to go to sleep later each day will not ruin
it.
Moreover, people isolated from external stimuli tend to fall into
cycles
slightly longer than 24 hours which also explain why it is easier to
prolong the
day rather than to shorten the night.
Lifestyle and
personality are critical here. Owls may show lots of
excitement for learning as this excitement is the main factor that
makes them
owls. On the other hand, larks can make better use of early morning
hours where
they can study in quiet at the time when their brains are most
refreshed. The
formula for best learning is then (1) to go to sleep in accordance with
one's own body clock (i.e. when actually sleepy), (2) to get up
naturally (i.e. without an alarm clock) and (3) learn at the peak of
one's alertness (which in a natural rhythm should come shortly
after awakening).
Question:
Is it true that it is better to get shorter sleep in the night and then
take a few naps during the day?
Answer:
This approach is not likely to benefit your health or
learning. Most
of all, you should not artificially shorten the night sleep! As for the
naps,
there is only one major trough in alertness during the day in siesta
time (at
least in healthy adults). Taking more than one nap is not likely to be
needed. Experts on insomnia argue against naps as
these may keep people up at night. If your nap lasts only 5-30 minutes
and does
not affect your ability to fall asleep in the night, it will probably
help you
be more alert in evening hours. See: Good sleep, good learning,
good life
Question:
Isn't Good sleep for
good learning article overly dramatic? Most of my friends cut
their sleep with
alarms during the week and they aren't dumb people!
Answer:
The cigarette metaphor is very useful in understanding the
problem of sleep
deprivation. A cigarette smoker will often tell you: I feel
great when I
smoke! I cannot imagine life without cigarettes. I do not think it is
unhealthy.
If it is, why does it make you feel so good? Only
epidemiological research
demonstrates the multi-billion dollar impact of smoking on the economy.
Similarly, seriously sleep deprived people feel miserable enough to
succumb to
their body clock demands. When they get a chance to catch up, many
report
feeling better than if they had not been sleep deprived in the first
place. It
is nearly impossible to notice a damage to memory consolidation. Only
scientific
research reveals the truth, and the true societal cost of sleep
deprivation and
shift-work still remains to be fully quantified
Question:
If any change is stressful, can free running sleep be stressful too?
Answer:
Saying that any change is stressful is a generalization going
too far. Changing your T-shirts daily does not imply stress. In
addition, the degree of change is important. The same change can
produce overstress or be a welcome factor in life depending on its
degree. Watching news on TV can provide a creative
adrenaline-based incentive. Watching September 11
news might have left people in overstress for weeks.
Letting your sleep free run does not imply any degree of stress, unless
free running sleep itself produces changes in your schedule that might
be stressful. If you eat your moderate meals frequently when you feel
hungry, you are likely to experience less stressful change than when
you eat them at pre-set lunch hours. Free running behaviors, by
definition, free your organism to adapt to its internal needs. As such,
these can be considered anti-stress factors. It refers to sleep, eating
habits, exercise, and other physiological needs
Question:
The Good sleep for
good learning article says that I cannot remember if I do not
sleep. However, when I
do not get enough sleep, I have problems with concentration, most of
all. What
is worse then, not sleeping before or not sleeping after
learning
with SuperMemo?
Answer:
Despite what is written in Good sleep for
good learning about memory consolidation in sleep, not
sleeping before learning would probably be more
expensive in terms of
lost work. If you do not sleep after learning, you
will not consolidate
memories and this will most likely affect retention of new
short-interval
material. However, if you do not sleep before learning,
you will
dramatically decrease your retention in a given session. This will
naturally not
be a result of forgetting. It will simply result from problems with
focusing on
the material and getting poor scores on otherwise well-remembered
material.
Consequently, many long-interval items will reenter the learning
process with
short intervals. This always significantly increases your workload
Question:
I read that too much sleep may result in a "worn-out
syndrome". Good
sleep for good learning article seems to contradict it! What
is the explanation?
Answer:
The "worn-out syndrome" can be observed when a heavily
sleep-deprived individual sleeps unusually long (above 13 hours). It is
very
difficult to persist in long-sleep routine as the sleep-regulating
mechanism
will quickly regulate the length of sleep to a more typical length. On
one hand,
the "worn-out" syndrome might seem to persist if the sleep period is
wrongly adjusted to the circadian cycle (see the section on hypersomnia
above); on the
other hand, the "worn-out" observation is usually
produced by those who cannot get enough sleep during the week and then
sleep
long on the weekend. In the latter case, follow-up observation is often
impossible due to next week's obligations. This deepens the wrong
conviction
that too much sleep is harmful. Healthy individuals cannot
take "too
much sleep"! Their brain will simply produce natural waking
up at the
right time
Question:
Sometimes I sleep over 9 hours and still feel tired. Usually
8.5 hours is
enough for me. What could be causing it?
Answer:
Most probably you are sleeping against your circadian cycle.
This could
occur most likely after a major shake-up in your sleeping rhythm (e.g.
after a
few all-nighters, or a few days of waking up very early with alarm
clock, etc.).
Try to stick to regular sleeping hours and understand
your circadian cycle. Many long-sleepers occasionally do not
get enough
despite sleeping quite long. Trivial factors such as stress or weather
can
easily put you out of synch
Question:
I live in a small apartment with my parents and two brothers.
I cannot use
your advice on free running sleep. It would be impossible to
coordinate with the
rest of family
Answer:
You can still try to free run. If your sensitivity to
zeitgebers (esp.
light) is good,
you do not necessarily have to run in non-24 hours cycles
Question:
If I did not use alarm clock for my after-dinner naps, I
could wake up at 10
pm! This is not realistic!
Answer:
If your nap launches you into a 4-5 hours sleep, you are
dealing with a case
of severe sleep deprivation! You should start off
with getting enough
sleep in the night. In other words, you need to give up the alarm clock
in the
morning as well. If you use the alarm in the morning, you enter into a
vicious
cycle of sleep deprivation and perpetual dependence on the alarm clock
Question:
What for should I measure the time between night sleep and
the nap? Can't I
just nap when I'm tired?
Answer:
Napping is a skill. Many people cannot nap even if they are
sleepy.
Measuring the time should help you optimize the timing. Optimally, your
tiredness will not be visible enough to easily guess the optimum
timing. If you
measure the time between night sleep and the nap, you will notice that
the
length is always the same (variations depend on the quality of sleep in
the
night). In other words, this helps you figure out the timing of your
circadian
dip even on days when you do not feel tired
Question:
Perhaps short periods of sleep deprivation are bad because they are a
source of stress. But how bad it can be depends on how can you handle
stress
Answer:
It is true that the turmoil in the cortisol-epinephrine
system will make you more
susceptible to stress in sleep deprivation, but it is not true that
stress management can be a solution to sleep deprivation. It is true
that a good diet might improve the health of a smoker, but diet alone
does not solve the problem of smoking. The only ultimate solution to
smoking is no smoking. Similarly, the only ultimate solution to sleep
deprivation is sleep
Question:
I like the idea of free running sleep. It seems to work nice.
I work from
home and getting up late is not a problem. However, how do I
synchronize with my
wife?
Answer:
If you both try free running sleep, your will often be
surprised to find out
that it is easier to synchronize with each other than with the rest of
the world
(esp. if you have similar interests and daily routines). Probably one
of you
will just get up slightly earlier and work as a strong zeitgeber for
the other.
The problem will appear only when the length of your cycles differ
substantially. In such cases, instead of being a zeitgeber, the other
person
becomes a substitute for an alarm clock
Question:
I have read hundreds of articles on the web and they all
say that
naps should be avoided! Good
sleep for good learning article seems to say the
opposite
Answer:
You are probably referring to articles related to insomnia.
Indeed, people
who have problems with falling asleep in the evening, report that
avoiding naps
makes the problem less severe. However, this is nothing else than
promoting
night sleep by increasing daytime sleepiness. In free running
conditions, naps
usually come early, are short and do not affect the ability to fall
asleep
quickly in the evening. On the other hand, they certifiably increase
the
intellectual performance in the second half of the day (cf. Aschoff,
Dinges)
Question:
I heard a fatigue expert say that she recommends coffee just
before the nap. Good
sleep for good learning article contradicts this. How do you
explain that?
Answer:
Probably the expert referred to a quick restorative nap, e.g.
in case of a
drowsy driver. Good
sleep for good learning article tries to find the optimum for
your intellectual
performance. If you drink coffee before the nap, you are likely to
awaken
earlier as a result of caffeine kicking in. This may be a desired
effect if your are in a hurry to combat fatigue. However, an optimum
nap in a free running cycle will
naturally last
no more than 30 minutes, and its effect may be short-lived if it is
artificially
cut short with a cup of coffee
Question:
I read on the net that there are systems that can put me in theta
brainwave. 30
minutes of theta is supposed to replace four hours of sleep. Is this
true?
Answer:
No. This is a false claim that has no scientific basis
whatsoever. Similar
claims should disqualify the site your are visiting as a reliable
source of
information. As a counterbalance, we would rather recommend: Skeptic's
Dictionary for the New Millennium with valuable information
on how to
critically evaluate web content. Interestingly: Theta waves correlate
with
learning which increases the demand for sleep
Question:
If I wake up early in the morning, say at 4 am, what is the recommended
course of
action? Shall I try to fall asleep or get up and work?
Answer:
Probably you should make your decision on the basis of how
fast you believe you would be able to fall asleep. If you do not think
the sleep is coming
soon, it is definitely better to get up and work. This way you will
gain in three ways:
The best method for falling asleep fast is to go to
sleep at the right time
Question:
How can I fall asleep faster without having to think so much about what
is happening in my life?
Answer:
There are two weapons against racing thoughts before
sleep:
As for sleep management, there is only one sure method: to fall asleep quickly, you have to go to bed at the right time. Racing thoughts are an indication that you went to bed too early, i.e. not being in the right moment of your sleep cycle. If you are extremely tired due to sleep deprivation, it may still not be enough to fall asleep. A huge number of people go to sleep very tired but cannot fall asleep due to stress or due to worrying about how little sleep they will get. The best solution to this problem is free running sleep, i.e. going to sleep only when you feel you will fall asleep immediately. However, this method, for majority of younger people, will result in getting up later and later. In other words, it is incompatible with a normal lifestyle. In such cases, the problem is unsolvable. You need to put up with a degree of stress before sleep, some insomnia and some sleep deprivation. Various methods exist to alleviate the problem (e.g. timing exercise, bright lights therapy, etc.) but they do not resolve the core problem. Only a change in lifestyle could provide a satisfactory answer
The function of sleep is not muscle regeneration
Question:
According to what I've read in body-building literature, sleep is
necessary for muscle growth and repair
Answer:
If you do not get enough sleep, your body building effort
will be ruined. That is true. However, the only known evolutionarily
justified function of sleep is
the optimization of the memory storage. In other words, your muscles
need your sleep, but you do not sleep because of your muscle needs.
For the organism to cope with muscle regeneration, there is no need to
shut off the central nervous system, and make you unconscious for a
third of your life. If REM paralysis was to play this role, it could be
enforced at the level of the medulla oblongata without making you
unconscious. If growth hormone secretion was to play a role, it can
also be upregulated in
abstraction from the state of the central nervous system. You may list
many other benefits of sleep for muscular regeneration but none will
require the state of sleep itself. Using sleep for muscle regeneration
would be as
sensible as shutting down the government in order to fix a highway. The
belief in the role of sleep in regeneration comes from the feeling of
being "broken down" and "unrefreshed" once you do not get enough sleep.
However, you do not feel crushed because of the damage inflicted by the
lack of sleep.
Your state is simply your body's own defense against not getting enough
sleep. You can cheat those defenses to a limited extent with caffeine
or by waiting for the suitable part of the circadian cycle. No real
harm is done. One night of good sleep, and your body is back
to shape. The only true damage inflicted by sleep deprivation is to the
fabric of
your memory. Unfortunately, this damage is imperceptible, and the
universal perception is that sleep is cheap
and can easily be dispensed with
Sleep is needed for optimizing the memory storage
Question:
Last I heard, it was an enormous mystery to sleep researchers what the
purpose of sleep is, though there were a number of theories. If you
search
Encarta Online, you will read
"Although no one knows for sure why we sleep, there are a
number of
theories"
Answer:
Your perception is not unusual.
As with all inventions and theories, they go through some teething
trouble and then wait long for a social invention. Some inventions are
accepted and developed quickly (e.g.
Guttenberg's print, Tesla's AC current, etc.), others linger for years
in oblivion (e.g. Babbage's "computer" or Tesla's or Nelson's "WWW").
Some theories are
obviously correct and are accepted quickly (e.g. Newton's laws of
gravity), others
linger for decades due to (1) lack of "convincing" evidence (e.g.
Wegener's continental drift), (2) religious considerations
(Copernicus's
heliocentric system, Darwin's theory of evolution), or plain bad luck
(Mendel's
laws of genetics).
Luckily, the evidence for the role of sleep in learning is so
convincing, that no serious scientific conference on the physiology of
sleep will include more than a few
mavericks with their own alternatives. Naturally, every community has
its Peter
Deusberg
who can put the spanner in the works. Hence the editors of Britannica
or Encarta must
exercise extreme caution in adopting recent scientific findings. A
statement
"there are many theories of sleep" is safe and
obviously true. However, the research community
is more than a decade ahead of this statement, and the focus is not on if,
but on
how. Incidentally, the Encarta
articles on sleep were contributed by
Prof.
Jerome M. Siegel, perhaps the best known opponent of the
position that
sleep is involved in learning
Free running sleep is best
Question:
What will bring more benefits: free running sleep or
ultra-dian rhythm
of 4 hours? Why?
Answer:
By definition, free running sleep is best. After all, it is
dictated by your body's internal clock.
4-h ultradian rhythm has been invented by sailors who had to stay awake
for long stretches of time.
Ultradian rhythm is unnatural and can be quite unhealthy. For ultradian
sleep to be harmless, you would need to first entrain it and then
maintain it with free running sleep. If you try
it in real life, you will get a very definite answer to your question
Mid-day crisis is best resolved with a nap
Question:
Each day there is a moment when I am unable to focus on some task, get
tired, and less effective. Drinking coffee does not help. What should I
do?
Answer:
First thing to try is a mid-day nap. If the crisis point
arrives in between 5th and 9th hour of your waking day, retiring to a
peaceful location for a nap (without an alarm clock) is highly likely
to solve the problem. Try to time your main meal before the nap. If
napping does not help, you should carefully analyze your sleeping
schedule and read:
Good sleep for good
learning. You probably do not need to seek professional help
unless your problem cannot be resolved with free running sleep or if
you cannot afford napping or free running sleep
Dreams of blind people help us understand the
physiological role of sleep
Question:
Do blind people dream?
Answer:
Yes. Their dreams are more auditory and tactile in nature
which confirms the role of REM in replaying daily experiences and
optimizing memories. They do not show the typical eye movement pattern
in REM sleep either
Reducing sleep without alarm clock
Question:
Is it possible to reduce sleeping hours without using alarm clock?
Answer:
Yes. If you free run your sleep, the quality of your sleep
will increase, and your average sleeping time is likely to decrease (as
compared with sleeping it out in irregular rhythm patterns). You can
also reduce your sleep time by intending on waking up early. However,
thinking of getting up earlier is stressful and may negatively affect
the quality of sleep.
Afternoon downtime
Question:
My peak time for learning is from 7:00 pm to midnight. I don't feel
sleepy and my mind runs like a tiger. My problem is that when I come
back home from the university at 3:00 pm, I am always less effective.
Then I try to get some sleep
Answer:
Your being less alert at 3 pm is quite natural. Most of us
experience a trough in alertness around that time. Your peak evening
performance might indicate a minor DSPS problem, which is also quite
typical for studying adolescents. If you get up without an alarm clock
in the morning, you have nothing to worry about. You can use your low
after-school time for some more relaxing activity. No need to feel
guilty about it!
6.5 hours of sleep per night might be just right
Question:
You disagree with the recent study on the optimum
length of sleep. I understand your point. However, Dr Kripke says that
those who sleep 6.5 hours per night should not worry. I sleep just
about that. Why do you say I have reasons for concern?
Answer:
Probably you have misread our message on optimum sleep. No
one should worry about sleeping 6.5 hours or
even 4 hours, as long as he or she sleeps naturally, wakes up naturally
and feels refreshed.
The key point then is in how you get your 6.5 hour. If you wake up
without an alarm clock and feel alert throughout the day, you have all
reasons to call yourself a good or even excellent sleeper (few people
can live without an alarm clock). On the other hand, if you wake up
with an alarm clock and feel tired, you are certainly doing yourself a
harm. There are naturally many stages in the middle which cannot be
answered through a simple FAQ. It is not how much we sleep but how we
sleep. Our message is mostly targeted against the use of alarm clocks
and sleeping pills in regulating sleep
Waking up short of breath may indicate sleep apnea
Question:
My Mom is 50 and looks healthy. However, every night when she goes to
sleep she would wake up short of breath as if always coming from a
nightmare. She would say she feels like she's falling to a deep valley
Answer:
The symptoms described are typical for sleep apnea. This
means that your mother may have
a problem with breathing during sleep. This wakes her up and ruins her
sleep. Exercise, sleeping on the side, and weight loss may help in mild
cases, but do not fail to
insist your mother see a sleep expert. Sleep apnea may result in an
increase in blood pressure and a heart condition. A patient may look
healthy and normal, but in the long run his health may suffer
substantially
Occam's razor for SleepChart
Question:
I think that what you are proposing with regard to how we manage our
sleep is just far too complicated and that Occam's razor needs to do a
bit of shaving here - I mean, come on! Sleep's as natural as breathing
air or drinking water and if you have to set up complicated charts and
experiments, and utterly eccentric sleep-activity patterns just so as
to get some decent shut-eye, then you must have a problem - but one
more of a psychological than a physiological nature
Answer:
Sleep will occur naturally in a natural setting. The trouble
begins when we interfere with nature using caffeine, alcohol, nicotine,
artificial lighting, 24/7 society, night-time entertainment, etc.
SleepChart
may seem complex, but it might still be the easiest way to predict the
optimum timing of sleep in free-running conditions (probably there are
no equivalent tools available as of Oct 2004).
SleepChart will only ask you when you go to sleep
and when you wake up (naturally). All computational complexity is
hidden in the background. The approximation procedure needs no further
input from the user and it predicts circadian lows as well as the
optimum timing of going to sleep. For those who are interested,
SleepChart can even disentangle homeostatic and
circadian components of sleep.
As we are dealing with the physiology of sleep, by definition, we are
indeed within the realm of psychology. The problem can be solved with
behavioral tools too. One of the most effective
tools is the application of free running sleep
Music and sleep
Question:
I want to be awake for 3 days with the help of my favorite music? Is it
possible?
Answer:
Unless you do a research on ravages of sleep deprivation, you
should never force your body to go against your natural sleep-wake
cycle! The longest natural waking period rarely goes beyond 20 hours.
Beyond that you must go to sleep. Otherwise you will negatively affect
your health and learning. You can use music as an
invigorating factor though. The rules applied here will be similar to
those for using coffee:
never use music, coffee or other stimulants to prevent
descending circadian
sleepiness. Use mild stimulants only on the ascending
circadian after you wake up from the night sleep (or after a properly
timed nap). In simple terms you can help your body wake up, but you
cannot try to prevent it from going to sleep!
Striving at lucid dreaming is a waste of time
Question:
What is your stand on lucid dreaming? Can this be used to enhance
learning, or creativity? How about personal growth, super-consciousness
and experiencing
hyperreality?
Answer:
Lucid dreaming is as useful for learning and creativity as
LSD. Striving at lucid dreaming is rather likely to disrupt your
healthy sleep and negatively affect learning.
During REM sleep, the prefrontal cortex should normally be
de-activated. Hobson's
AIM model of 3D sleep-wake space can be used to illustrate
the state
corresponding to lucid dreaming as a partitioning, in which the cortex
and the
rest of the brain occupy different points in the AIM space. Such
partitioning is likely
to interfere with the physiological function of REM sleep. It can be
compared to
eating your lunch while jogging (i.e. the situation where contradictory
targets
are fed to the nervous system). Using
auto-suggestive tricks to change the AIM state may affect neural
processes occurring
in sleep with unpredictable consequences that are not likely to be
positive. As for creativity, it is conceivable that LSD
(and less so lucid dreaming efforts) might boost non-specific
creativity or help understand the creative process; however, most of
the mankind's creative breakthroughs occur when a healthily refreshed
mind focuses on solving a specific problem. Hallucinatory haze is not
helpful in directing creativity towards useful purposes.
Creativity is a game of chance. You should look for ways of consciously
directing the creative process rather than to increase its randomness
indiscriminately. As for super-consciousness and hyper-reality, you are
addressing the question to a wrong party. At supermemo.com, we
firmly intended to remain within the realm of science.
You cannot "more or less" free run you sleep
Question:
I have been struggling with getting a good quality sleep for years (my
symptoms resemble DSPS). I more or less followed a 'free running sleep'
during my student years: every night
I went to bed later and every morning I woke up later until I would go
to bed at around 5 am. But I just could not continue this shifting
scheme. So I always tried to go back, with getting up early and slowly
changing my rhythm
Answer:
Your actions are understandable and typical for
DSPS. However, you cannot "more or less" free-run your
sleep. Once you try to "go back" to the old rhythm, you violate
free-running sleep principles and you cannot call it free running
sleep any more. Your experiences will not translate directly to the
free running condition. In other words, to draw your conclusions on
free running sleep, you have to truly give up the alarm
clock and all other forms of regulating sleep (e.g. going to sleep
later than
natural, etc.). If this is not possible in standard circumstances, you
could try during the nearest vacation.
If you collect data on your sleep cycle, please forward for analysis
and further
comments
All forms of sleep "regulation" should be avoided
Question:
Even without an alarm clock, I noticed that late falling asleep gives
me a bad night. I usually get up at 6-8 no matter when I fall asleep.
After one New Year's Eve, I fell asleep at 7, and got up at 8
Answer:
Yes. This is exactly what you should expect in a healthy
individual. Your arising hour is strongly dependent on your circadian
cycle and it is only slightly shifted by going to sleep late. As much
as an alarm clock, delaying sleep is also a form of sleep regulation
and should be avoided. The only exception is when delay is executed in
order to fit the circadian cycle. Delaying retirement may be less
drastic than using the alarm clock (the sleep cycle is not interrupted
artificially), but is also highly detrimental to sleep quality. As for
your New Year's Eve, you would better wait until the next sleep cycle
and go to sleep, for example, only at 15-19, so that your strong
homeostatic sleepiness would let you sleep until your evening circadian
low kicks in giving you many hours of sound sleep.
Better yet, you could cut your party short at an earlier hour
The good sleep may not apply to you
Question:
What can I do living with my wife and son in one bedroom apartment? I
can only try to get rid of the alarm clock, but still most of my
wake-up calls come from my son being hungry
Answer:
Admittedly, most of the principles of good sleep are
impossible to meet for many. In richer countries shift work, stress, or
family life are to blame. Elsewhere poverty or little understanding of
health matters are only a few of factors that make good sleep so
elusive. For young parents, a child is a factor that adds an
insurmountable challenge. Probably all you can do is to maximize love
in the
household, try to take rational duty shifts with your wife, and get as
much sleep as you can whenever there is an opportunity. With time it
will become easier and easier to synchronize the family life and give
everyone a chance to begin the day all smiles
Sleeping in wrong hours may be as bad as not sleeping
at all
Question:
If deviations in habitual sleep time produce performance losses
equivalent to those produced by shortened sleep (Taub & Berger,
1976), does it not imply that sleep deprivation is not as important as
the
disruption to the circadian cycle itself? Perhaps sleep is not as
important as
keeping the circadian rhythm?
Answer:
No. It is true that sleep in wrong hours may be worse than no
sleep at all but this only indicates that sleep needs to be properly
synchronized with the circadian cycle to play its physiological
function. A delicate neurohormonal balance triggers individual phases
of sleep that interplay in optimizing memory storage. The quoted
research should only strengthen
the conviction that the societal damage produced by alarm clocks is
enormous
Free running sleep is a blessing
Question:
Sleep is important, but there is no conclusive study showing temporary
sleep deprivation is terrible
Answer:
You are right that there is no evidence of "terrible" damage
produced by sleep deprivation (except for horrifying truck accident
statistics, airtime disasters, etc.). However, if you ask anyone who
tried free running sleep for more than a month about the cost of sleep
deprivation, you are likely to hear a very definite private research
conclusion:
"Never back to the days wasted by lost or irregular sleep".
The contrast
between good sleep life and bad sleep life is so dramatic that you will
find no one who hesitates about the difference once it is exposed in
practice. As adrenaline and cortisol are good masks for sleep
deprivation, the above is particularly true in creative professions
with mild to severe adrenaline deficit
Free running sleep does not imply abnormal sleeping
habits
Question:
Is there a big difference between a normal sleeper and a free running
sleeper, if the normal one:
Answer:
What you have just described as a "normal sleeper" is by all
standards a lucky free running sleeper. The main criterion
of free-running sleep that has not been listed above is if the "normal
sleeper" uses an alarm clock. If you do not use an alarm clock or other
sleep control tricks, you are a free running sleeper. As
you indicate that your "normal" sleeper "sleeps enough", he or she is
not likely to use an alarm clock that would cut the natural sleep. As
he or she "feels rested", the sleep is most likely healthy and
physiologically sound. As he or she "listens to zeitgebers", the sleep
again seems to be regulated by natural factors. Your "normal sleeper"
can be considered lucky because in addition to using natural sleep, he
or she is able to sleep in regular hours, is rested and wakes up with
sunshine. As many people suffer from a degree of DSPS or ASPS, your
"normal" scenario may be difficult to reach for many. The DSPS/ASPS
problem is particularly painful in the student community, in
overstressed working population as well as in many elderly
The problem of waking up in the night
Question:
Why do I often wake up in the night?
Answer:
If you wake up during the night, you should
identify and eliminate possible reasons, esp. if you appear to wake up
tired. The reasons and the way to diagnose them are too many to
describe in a short answer. However, you should always start from the
simplest one: problem with the circadian rhythm. In simple words, the
timing of your sleep may be wrong. Partitioning of sleep is a typical
symptom of going to sleep too late or going to sleep too early. If you
are healthy, in free running sleep, you will rarely wake up during the
night; and if you do, the reasons will be quite obvious such as:
stress, noise, thirst,
coldness, full bladder, etc. However, if you attempt to regulate the
timing of your sleep, the partitioning of sleep (i.e. interrupted
sleep) will be a frequent result. It is possible to push your sleep
slightly ahead
or back (e.g. 15-25 minutes per day) without this negative outcome.
However, once you try to push too hard (e.g. more than an hour per
day), partitioning is almost inevitable. If you push backwards (i.e.
going to sleep earlier and earlier), you will
likely wake up early in the night, i.e. before your circadian low
ensures deep sleep. On the other hand, if you push forward (i.e. going
to sleep later and later), your circadian low will end before you
complete your sleep cycle. As a result, you will often wake up
earlier than expected. If this waking up happens very early (when you
push ahead
very hard), you will be tired enough to fall asleep again. In other
words, whichever way you push your sleep, it will not be properly
aligned with your circadian rhythm. You will then wake up early or late
in the sleep cycle depending on
at which end the misalignment occurs. In a vast majority of cases,
waking up problem can be resolved by going to sleep at the time when
your body calls for it. However, if free running sleep does not remedy
the problem, you may need to consult
a sleep disorders expert
Sleep period and genetics
Question:
I am sure that the free running sleep period
is not entirely determined by genetics
Answer:
You are right. Various factors in the daily schedule are able
to shorten or lengthen the period. Of the obvious ones, bright light in
the morning or melatonin in the evening may shorten the cycle. Exciting
activities in the evening will
lengthen it. The period changes slightly with seasons. It will also
change when you leave on vacation. It
often gets shorter with age
Sleep length depends on the circadian phase
Question:
Does the sleep onset hour affect the length of sleep?
Answer:
It may but it does not have to. The most powerful factor
affecting the length of sleep is the circadian phase. In a normal
patient, the circadian rhythm is aligned to the 24 hour period. Thus
the sleep onset hour will be directly related to the length of sleep.
Maximum length of sleep will occur with the sleep onset falling roughly
between 22 and 3 am (depending on the individual rhythm). However, in a
free running DSPS patient, this relationship is lost. In DSPS rhythm,
the graph of the function of the sleep length vs. the sleep onset hour
is horizontal, i.e. the
length of sleep does not change (on condition the rhythm is running
free without a disturbance). Here are a simple rules to determine the
expected sleep length:
Never go to sleep when you are not sleepy. Never force yourself to work through high sleepiness. If feasible, always go to sleep when you feel your body wants to go to sleep
Which component of sleep is best correlated with the
fresh feeling in the
morning
Question:
Which
phase of sleep is most important for the fresh feeling in the morning?
Answer:
Stage 4 NREM sleep ("deep sleep") correlates strongly with
feeling fresh.
However, a proper structure of sleep is also vital. To get lots of
Stage 4 NREM:
adhere to your circadian rhythm, exercise, and avoid NREM-suppressing
medication.
Although you get lots of NREM early in sleep, cutting down your sleep
with alarm clock will likely take away all freshness as soon as the
homeostatic
sleepiness kicks in. For that reason, you should sleep as much as your
body
wants to
Owls, larks and procrastination
Question:
Is it true that owls are greater procrastinators than larks:
http://dubinserver.colorado.edu/prj/jph/index.html
Answer:
The
presented mini-survey is flawed. Depending on the elected population
sample, the
correlation might yield highly varied results. There might be a link
between a circadian type and procrastination. Obviously, people who
sleep poorly are more likely to procrastinate. This comes directly from
an impaired prefrontal control in sleep deprived people. However, it
would seem likely that all forms of departure from the standard 24
hours entrainment would affect executive control. This way, "normal
people" should be best at executing their own resolutions. Departure
towards both DSPS or ASPS might negatively impair self-discipline.
As distribution of DSPS and ASPS in different age groups varies,
running a
survey among students is likely to link owls with procrastination.
However, the
same survey among retirees might yield an opposite result. ASPS is by
far more
frequent in older people due to inherent changes in the circadian cycle
that
occur with aging. Naturally,
free running sleep is likely to dissolve the link between
morningness and procrastination.
In conclusion, good night sleep is certainly a good remedy against
procrastination
It is possible to fall asleep immediately
Question:
It seems that a good sleeping rhythm relies on the ability go to asleep
immediately, which I do not have, even in the most tired physiological
state. It takes me around one hour to fall asleep, almost regardless of
how tired I am
Answer:
You need to remember that your "sleep tiredness" has two
components:
homeostatic and
circadian. You believe that you are awfully tired, but if
this is only a homeostatic tiredness, you can toss and turn for many
hours. Homeostatic tiredness grows quickly in conditions of sleep
deprivation, while circadian tiredness comes only at a specific time in
reference to your body clock. If you are tired of
wakefulness but your body clock is not ready, you will not fall asleep.
Free running sleep resolves this problem in majority of cases. It might
not work if there is an underlying health problem (e.g. excess
catecholamines, thyroxin, cortisol, overstress, etc.)
Multiple awakenings in the night
Question:
I have a recurring sleep pattern, which I do not understand. There are
times, sometimes for a few weeks at a time, where I will go to bed at a
normal hour (9-11pm). I go to sleep when I'm tired. However, after
sleeping 4-5 hours, I wake up briefly every hour. I am awake for just a
minute, then go back to sleep. I typically will get up around 6:30am.
So, a typical night in this scenario might look like this:
Answer:
There does not seem to be anything troubling in the above
rhythm. The best part is that you wake up without an alarm clock and
feel refreshed.
The brain has a top-quality system to let you know when you did not get
enough
sleep; you just feel miserable. Multiple awakenings during the night
are not unusual. However, most of us are not aware these short breaks
ever happen. If there is a trip to the bathroom in the meantime,
reducing fluid intake 2-3 hours before sleep might
help (naturally). You seem to get a good 4-5 hours of deep sleep and
then wake up briefly after periods of REM-rich sleep. Nothing in that
rhythm indicates departure from the healthy brain physiology. The
periodicity of the above symptoms could be related to seasonal or
temporary changes in hormone levels. On the face of it, you got nothing
to
worry about. Nevertheless, it is always a good idea to seek second
opinion in health matters
How to improve evening alertness
Question:
Do you have any suggestions on how to acquire optimum alertness at a,
for me, unusual, evening time of the day?
Answer:
You will always obtain best alertness if you adapt the timing
of activities to your natural rhythm, and not if you try to adjust your
body clock to the outside world.
A simple alertness booster, such as caffeine is only likely to last for a short while, it is not likely to eliminate the reduced capacity for learning, and worst of all, it could interfere with your sleep cycle making things worse in the long run.
An afternoon nap could do wonders if properly timed and executed along the principles of the art of napping. A creative evening is a norm among skilled nappers.
However, nothing would work as well as moving the activities that require high alertness, learning or creativity to the time where the alertness is maximized naturally (which for most healthy people is not long after awakening from the night sleep)
Variable sleep length is an indicator of
non-free-running sleep-wake cycle
Question:
If the length of sleep is constant in free running sleep, why do sleep
logs of DSPS patients show a clear relationship between the sleep onset
hour and the sleep length?
Answer:
Such a relationship will only show if the rhythm isn't a
perfectly free running rhythm. Rarely are patients able to disconnect
their sleep needs with their need to perform their daily duties in the
society. As a result, DSPS patients who claim to free run will often
learn tricks to "manipulate" their sleeping rhythm (e.g. trying to
accelerate the phase shift before an important appointment, etc.). In
an undisturbed free running rhythm, the length of sleep should remain
constant.
25-hour sleep
cycle
Question:
Why is there the 25 hour
sleep cycle built-in in us when the Earth's cycle is only 24 hours?
Answer:
Internal clock runs at
above 24 hours due to the fact that we can easily synchronize the day
with our body clock by the use of zeitgebers (mostly sunlight). This
way the oscillator with a slightly longer period is set to synchrony
with the daylight by a minor
SCN-mediated reset. This provides for a very stable oscillation. This
mechanism goes awry by the use of artificial lighting as well as due to
providing us with exciting evening activities such as watching TV,
surfing the net, playing computer games, reading, etc. People suffering
from DSPS could experiment with light dimmers, toning down their
schedule in the evening, properly timed exercise and bright light in
the morning. People with ASPS should use opposite measures (e.g.
3000 lux light in the evening)
The three things you need for good sleep
Question:
My name is Kevin. I am in grade 8. I am doing a science fair project.
What do you think are 3 things necessary for a good night of sleep?
Answer:
There are many things we need for sleep. Some
of these are obvious, e.g. a comfortable bed. Those things are hard to
compare.
It is as much as wondering what we need more for life: the brain or the
heart.
We simply need both. Let's rephrase the question to make it useful for
an
average poor sleeper. What are the main 3 things people do wrong when
trying to
get good sleep?
These might be top 3 bets for good sleep:
One might hesitate about the third point: perhaps avoiding stress is more important than avoiding sleep-affecting substances. However, most people cannot run away from stress in their job or in family life. It is far easier to skip the evening drink or a cup of coffee than to resolve a gnawing conflict at work. Hence the third choice.
You may now be wondering what you should do if your body tells you to go to sleep at 3 am, while your school begins at 8 am. Nobody has yet provided a satisfactory answer to this question. Ideally, the school should adapt to your rhythm. Some schools tried this. But then … your rhythm may shift further and later school hours stop being helpful. Returning to the Stone Age, or to the times before electricity is not an option. We can only hope that the science of sleep will come up with a cheap, healthy and lasting solution
Alarm clocks that detect your sleep phase do exist
Question:
I read somewhere that there's an alarm clock that's being developed
that's keyed to the users sleep cycle
Answer:
Yes. This alarm "clock" has been developed millions of years
ago. It makes up part of our brain and is responsible for the release
of "wake up" hormones (such as cortisol) at the time when we should
optimally get up (i.e. once we are through with all vital sleep
phases). This alarm clock is smart and adjustable. If it is not
interfered with much, it
perfectly aligns our sleep cycle with the cycle of day and night. And
the best part is ... it comes free with installation at birth to every
healthy
individual
You cannot learn much from tapes while you are asleep
Question:
Can I really learn by listening to tapes while I sleep?
Answer:
No. Your brain uses sleep to do memory housekeeping. This is
a very important process without which learning is not possible. Using
a computer metaphor, you can imagine that during waking hours, you load
information into your memory, while during sleep you do disk
defragmentation. Naturally, your computer can survive without
defragmentation. Your brain will not survive without sleep. All
learning processes grind to a halt in conditions of sleep deprivation
(i.e. insufficient sleep).
While you are asleep, the brain is busy with memory housekeeping, and
it cuts itself off from the external world. For the most part, this
means that it will perfectly ignore the tape playing in the background.
However, if the tape is noisy or annoying, it may disrupt your sleep.
As a result, you might be actually learning worse when using the tapes.
It may happen that you recall pieces of the tape playing throughout the
night. This is because of the way the brain works in sleep. It goes
through a series of well-planned cycles. At the end of each cycle, your
mind will be very close to the waking state. It may pick up pieces of
information. However, those states may result in various forms of
hallucination. In other words, you can mix things up and rearrange
information into a new meaning. You can learn things upside down!
All in all, stay away from quacks offering you learning in sleep! The
best thing you can do for your learning in the night is to sleep as
much as your body wants. Try the so-called free-running sleep.
Free-running sleep is sleep dictated solely by your brain. If you can
afford it, throw away your alarm clock. Your alertness, your joy of
life and your learning powers will be at the maximum
Non-24h free-running sleep might be a lesser evil
Question:
I found your sleep article too extreme. If you work solidly 8 hours a
day, have 3 decent meals, have a proper family life, and treat other
people as human beings, then in the evening you go to bed happily
knocked out and wake up next morning happily refreshed. Surely this is
as it always has been for most people throughout history and surely
this is how it will always remain
Answer:
Unfortunately, your perception is not unusual. Those who are
lucky to experience good sleep will always find it difficult to
understand those who have problems in the sleep department. This
attitude is not much different, however, from telling a clinically
depressed person:
"Pull yourself together", or expect a heroin addict
to go cold turkey and instantly return to normal life. A tortured
insomniac will only get more upset with himself or herself if (s)he is
told that sleepless nights come from
"unsolid work", "indecent meals", "improper family life" or treating
others "inhumanely". The trouble stems from the clash of biology with
modern lifestyle. With the arrival of artificial lighting sleep
disorder statistics skyrocketed. These were only made worse by
television, computer games and the Internet. With the advent of mobile
telephony and instant messaging, insomnia and sleep phase disorders
seem to reach epidemic proportions. Fewer people are able to leave work
behind, cope with stress, or give up evening activities. Without a
major change in lifestyle or a breakthrough in circadian control
methods, people affected with lifestyle-related sleep disorders are
faced with a choice between a daily sleep deprivation misery and
radical solutions such as throwing away the alarm clock. Certainly, we
can expect science to come up with answers to the problem. Until that
happens though, waking up "happily refreshed" remains a
privilege of a shrinking subset of the population in industrialized
nations
If you love to wake up at 3 pm, doing so might be
your healthiest option
Question:
I find that I seem to sleep best (i.e. sleeping just the right amount
and awaking feeling refreshed) from 6-7 am till 2-3 pm. I can
consistently go to sleep those time frames. Going to sleep any earlier
or later is a struggle for me. When I've made a point of going to sleep
at midnight or any earlier than 6 or 7am then I still sleep until 2 or
3pm. Sometimes this has resulted in my getting 12-14 hours of
sleep--which is an annoying waste of time, and also seems like poor
quality of sleep. In other words, when I go to sleep at midnight, I
really can't wake up until 2 pm or so--even if I set multiple alarm
clocks. What's worse is that the sleep doesn't feel refreshing. I feel
groggy. Your research seems to indicate that I should be able to set my
sleeping times to whatever I want them to be; be it going to sleep at 9
pm and awakening at 5 am ... or any desirable setup
Answer:
It is possible to use chronotherapy to shift your sleeping
rhythm, but it is always a struggle if it goes against your natural
inclinations. In other words, there are ways for you to start falling
asleep at midnight and waking up early, but your description indicates
that it is unlikely to be a stable sleep pattern. Your 14 hour sleep is
easily explained with the fact that your circadian low time falls
somewhere between 9 am and 2 pm. If you succeed in falling asleep at
midnight, your sleep between midnight and 6 am is of little biological
value. As a result, you may indeed feel groggy and waste extra hours on
unproductive sleep. A very strong rule of good sleep says that it makes
little sense to try to sleep when you are not sleepy!
Your sleep rhythm is a combination of lifestyle, your particular sleep
control system, your interactions with the environment, etc. Your
biology seem to interact with your environment in such a way that
waking up at 15:00
becomes a natural and stable routine. If it does not ruin your life
professionally, sticking to this rhythm might be chronobiologically
simplest, cheapest and, paradoxically, healthiest solution. However,
you should investigate what factors contribute to your staying up late,
and perhaps shift the balance to slightly earlier hours, e.g. by
avoiding late night TV, lighting, work with a computer, etc. You could
also add some intense exercise and exposure to strong light in the
morning.
The fact that it is possible to shift your rhythm is not a
recommendation to do so. You have to weigh up pros and cons. It is
probably healthier to synchronize your sleep with night-time, but
forcing such an unnatural synchrony may cause more damage than
good.
Your best options are: keep studying chronobiology, keep studying your
own sleeping preferences (e.g. use
SleepChart
to plot your patterns), and try tiny experiments with what factors help
you shift your rhythm to more "standard" hours.
Can learning be arousing?
Question:
I found the following on Dr Dement's website in his guides to better
sleep:
"Avoid heavy studying or computer games before bed, they can
be arousing". Do you question one of the greatest authorities
on sleep?
Answer:
With due respect, the
quoted sentence is quite imprecise. There is no doubt that computer
games are arousing and should be avoided. However,
"heavy studying" can take many forms. If you study
for an exam, and this brings stressful images of the exam itself, you
can indeed be aroused. If you study a fascinating subject that
monopolizes your thoughts, it can be arousing as well. Similarly,
learning in a
brightly lit room may slow down the descent to sleep. However, if you
extract the pure learning process devoid of stressful associations,
light, social aspects, etc., you will come to a different prescription.
Learning is definitely associated with the homeostatic component of
sleepiness, and can promote sleep.
Here are the suggestions:
NASA study contradicts your claims in "Good sleep"
article
Question:
Here is a webpage outlining a
NASA
experiment on
naps.
They say that while naps can improve 'working memory', they do not
generally improve general vigilance and alertness. This is obviously
contradictory to
"Good sleep, good
learning, good life" article which says:
"The drop in alertness [during midday] is magnified by a rich
meal and a short nap is likely to quickly bring you back to full
alertness"
Answer:
Various measures of alertness, vigilance, and/or working
memory should all correlate closely with your ability to learn or with
your ability to recall information from memory.
Data
produced with SuperMemo seem to indicate without any doubt
that your ability to learn increases dramatically after a nap, even if
the nap lasts just a few minutes.
In healthy subjects, some ambiguity may arise when naps are taken at a wrong time. A good nap falls roughly in the middle of a waking day. A nap that comes too close to the night sleep is likely to produce an "inertia effect" and may actually decrease alertness. Instead of being a nap, it comes closer in effect to an interrupted night sleep.
In simple words, if you are healthy, if you are skilled in the art of napping, if you take naps at the right time and, if you just feel better after a nap, you can be sure that your memory, learning ability, alertness, and other cognitive parameters will all be up. Naps are definitely good for learning. Except for people with certain sleep disorders (incl. severe insomnia), naps are good for health. We should all work to eliminate the stigma of laziness often associated with napping, and promote napping, incl. napping at workplace (if feasible and safe).
Sleep control mechanisms are imperfect
Question:
In the modern day with electricity and other stimulants at night, free
sleep will most likely result in a cycle greater than 24 hours. But for
our ancestors, who “could expect little but darkness and boredom past
sunset”, sunset and sunrise adjusted their circadian rhythm so that it
was a 24-hour cycle and fit with the 24-hour day. Since days are longer
in the summer than in the winter (sunrise is earlier and sunset later)
does this mean that our ancestors slept more in winter than in summer?
Was there a need for more sleep in winter? If they indeed slept more in
winter yet there was no biological need for more sleep, then it seems
that they must have been getting either more sleep than they needed in
winter or less sleep than they needed in summer
Answer:
Your reasoning is correct. Sleep control mechanisms are not
ideal for satisfying our sleep needs.
Sleep is primarily controlled by two mechanisms:
As the circadian component is influenced by light, variations in levels of illuminance will cause variations in sleep. It is conceivable then that we sleep less efficiently in winter (in terms of neural effects per unit time). Equally well, summer sleep might be less restorative. Eskimos cut off from civilizational influences sleep a few hours more per day in winter. It is then possible that the use of artificial light might contribute to efficiency of sleep (e.g. by delaying sleep onset); however, there is too little data to state that this could be a beneficial strategy. It could as well be deleterious by producing a sleep phase delay, reduced REM, lesser morning alertness, etc.
Prof. Jim Horne is right that in some circumstances we sleep more than we really need to. However, he goes too far when he compares sleep to eating (one might conclude that alarm clocks are similar to a healthy diet).
Excess sleep does not bring any tangible biological advantage for control mechanisms to favor long sleep. Conservation of energy is minimal, and the brain may actually use more oxygen during some sleep stages than when working on complex tasks. Even though lions might sleep 20 hours per day when there is shortage of food and water, humans, in normal circumstances, can only binge on sleep after periods of sleep deprivation, when sleeping in a wrong circadian phase, or when they experience health problems. There are many factors that might increase the demand for sleep (e.g. learning, exercise, etc.), or shift the sleep control mechanism to favor sleep over wakefulness (e.g. brain injury, infection, poisoning, hypothermia, etc.).
In conclusion, we need to realize that sleep control mechanisms are not perfect; however, we have not yet come with any artificial and certified ways of improving upon what we were given by the biological evolution. Natural free-running sleep is still the best way to accomplish healthy and refreshing sleep.
Why do synapses get weaker during sleep?
Question:
NYT has reported on a research (http://www.nytimes.com/2008/01/29/science/29obslee.html)
that sleep weakens the synaptic strength. At the same time, synaptic
strength
increases during waking. This seems to go against your own findings
that you
published on your website that indicate that during the day one's
ability to
recall facts seems to be waning (http://www.supermemo.com/articles/sleep-research-2007.htm)
Answer:
There is no contradiction between the fact that synapses get
strengthened
during waking and the ability to recall things drops at the same time.
First we
need to differentiate between (1) short term increase in synaptic
conductivity
that is a result of learning, and (2) the ability to recall long-term
memories
(as they are tested during learning with SuperMemo, which was used to
produce
the data).
Secondly, we need to look at the most likely explanation for the
weakening
recall during waking. The most coherent, attractive and best-supported
hypothesis says that the overload of short-term low-interference
networks is
responsible for a declining capacity of memory during a waking day.
This decline
cripples the working memory, and in consequence, it affects the entire
spectrum
of human cognitive capabilities. The main function of sleep would then
be to
redistribute, reconsolidate and optimize those short-term memories that
slow
down further learning. To put it metaphorically, the brain is like a
computer
that keeps loading chunks of data to its memory during the day. As the
memory
fills up, the computer slows down, and all applications crawl into a
halt.
However, if you test individual memory cells, you will notice that they
strongly
cling to their new data. In the night, the computer will gradually
organize the
chunks of data, remove discrepancies and duplicates, write down
memories to the
hard disk, and run a defragmentation process for easy and fast access.
Both the
increase in synaptic conductivity in wakefulness, and the decline of
learning
capacity during the day are well documented.
As for the decline in synaptic strengths during sleep, it also fits
well with
the present models of sleep and learning. One of the main functions of
sleep
should be to optimize the memory storage. This entails representing
memories in
most efficient way, i.e. so that they are most abstract, consume least
space,
generate minimum interference, and so on. That process should indeed
result in
reducing the overall cost of memories, and result in weakening of
redundant
synaptic connections.
Optimum nap time is best determined with statistics
Question:
How
can there be an optimum nap-time? Your article states the following:
· Homeostatic sleepiness increases with the length of time we stay
awake
· Naps are a needed solely to get rid of homeostatic sleepiness. Since
naps are meant to be kept short, I understand they can’t have a
circadian component. Therefore it seems logical that the two-processes
model does not explain the optimum timing for naps! After all, as long
as you stay awake your homeostatic sleepiness continuously increases
Answer:
Your
reasoning is correct. The two-processes model
of sleep propensity does not explain why we best nap at mid-day. The
two-processes model can be understood as the first iteration
of the ultimate model of sleep and wakefulness. Borbely, Achermann and
other researchers continue to enhance the model to better explain
various phenomena without making the model overly complex. The "optimum
nap time" is a concept that is best explained by mathematics. The
optimum nap time is the time, somewhere in the middle of your waking
day in free running sleep, that produces the maximum probability of
falling asleep
or the minimum average sleep latency.
You can easily plot your optimum nap time with SleepChart. SleepChart collects your sleep block statistics and can accurately point to the time of day where your naps might be most beneficial. The only conditions you need to meet are: (1) you need to free run your sleep (SleepChart uses a technique of predicting your homeostatic and circadian sleepiness that only works for natural, undisturbed sleep) and (2) you need a few weeks of your sleep data to make the reading accurate.
If you are a seasoned napper, you probably already know your optimum nap time, and you can use SleepChart to confirm your observations. If you are new to napping, you can start with naps in the exact middle of your waking day, and adjust the precise hour using SleepChart and your own observations. For example, if you cannot fall asleep, your nap might be too early. If you sleep too long, it might be too late, etc.
As for the biological explanation, it is worth knowing that there are a number of brain nuclei involved in sleep. Each is responsible for its own input processing. Each produces an output that depends on the input and its current state. Your napping will be affected by factors such as stress, temperature, exercise, weather, exposure to light, and many more. The circadian factors are also multiple. Apart from the levels of circulating hormones, body temperature, etc. there are different phases for REM propensity, SWS propensity, ultradian cycles, and other lesser components of your circadian pattern. Sleep researchers are only gradually finding out the enormous complexity of all these interconnected mechanisms. The sleepiness hump in the middle of the day is produced by homeostatic mechanism on one hand (i.e. you will not fall asleep easily if you take a nap too early), and by circadian factors on the other; for example, the forbidden zone of sleep that marks increased alertness in the evening. The paradoxical increase in the alertness in the evening (without or without napping) comes from the fact that there is a temporary increase in alertness hormones that can combat homeostatic sleepiness. However, this may also mean that despite the fact that you do not feel sleepy, your memory and your creativity won't be as crisp as in the morning (unless you took your mid-day nap). To make things more complex, late evening napping may also be affected by the possibility of catching onto the circadian low of the early night. This can potentially fragment your sleep and disrupt the healthy sleep pattern. Wrong timing of a nap produces negative effects that make some experts oppose napping as a healthy habit. All in all, even though the biology of napping is complex and not entirely understood, the statistics are quite clear and should help you learn to nap effectively even if you have always thought you were not a natural napper.
Maximizing attention
Question:
What do you think is the best way of increasing the span and quality of
attention in learning and in creative work?
Answer:
Attention
is subject to daily fluctuation along the circadian cycle. It is also
subject to homeostatic depression with prolonged mental work. In other
words, everyday you got only short windows of time when your attention
is
maximum. In addition, your total mental energy that can be extracted in
each window is limited. Understanding the timing of your circadian
rhythms and the natural limits on the attention span might be the first
step to take to optimize the timing of mental effort.
Once you know the optimum time for creative work, you can maximize
attention through neurohormonal control. Again you may need some
understanding of psychophysiology and your own mental needs to
accomplish this goal. Your primary tool here is passion. If you learn
how to become passionate about the task at hand, you are likely to
maximize attention. In addition, you can learn to apply lesser tricks
such as exercise, caffeine, ambient temperature, intervening tasks,
etc. Those need to be used with caution as they can easily backfire.
Again, nothing works better than trial and error backed up with some
knowledge of the physiology of mental effort.
Last but not least, in learning, you can substantially increase
attention of less interesting subjects is you use the incremental
approach.
Incremental reading
improves your attention
by including attention along your priority criteria. In incremental
reading, you can always temporarily de-prioritize the material that
undermines your attention. As the effect on attention is highly context
dependent, you can always find the best
moment at which you tackle a particularly difficult subject
How costly is is to skip nights of sleep?
Question:
If
I sleep well during most time of the year, how would it affect me to
skip 1 night of sleep or sleep just 50% of my needed hours 2 nights in
a row? How unhealthy is it to do this ~4 times a year in connection to
parties, birthdays, christmas, conventions?
Answer:
It is
not possible to quantify the effects of such violations. Most of
conclusions on the effects of sleep deprivation on health come from
restrospective analyses that make it hard to produce clear-cut
correlations. The answer falls somewhere within the scope of the
statement "it is definitely not healthy". Judging by the scope of
violations people commit on their sleep in general population, skipping
sleep 4x per year is not much. Your own body can probably provide you
with some measure of the effect. Some of the negative aspects of sleep
deprivation are exaggerated and disappear after a single night of good
sleep. Others may be imperceptible and more deleterious (e.g. when your
violations affect the phase of sleep in a way that tips you out of
balance for days to follow extending the damage for perhaps as long as
one week). The negative effects will affect nearly all systems in your
body as these all change function along the circadian cycle. Your best
strategy should be never to skip nights and, if possible, never use the
alarm clock. But if you do, the negative effects will add up in the
long term and will still be very hard to measure. You just cannot take
a copy of yourself to see "what if".
Insomnia may be
both biological and psychological
(insomniac,
Oct 31, 2010)
Question:
Do you think insomnia physical or psychological?
Answer:
There are many types of insomnia or many factors that contribute to
insomnia. For younger studying population, the most frequent cause of
insomnia is related to sleep phase problems. For students who need to
get up for school early, their sleep phase is often positioned too
late in reference to the desired waking hour. In other words,
the optimum sleep time comes too late. Sleepiness arrives too late, and
natural waking comes later by the same degree. Such a student will
always battle with sleep deprivation when going to sleep late, or a
degree of insomnia when going to sleep early. In that sense, there is a
physical/biological underlying cause. However, as sleep deprivation is
pretty unpleasant, a student may try go to sleep early (to ensure the
night is long enough), but be unable to fall asleep due to the early
circadian hour. If this occurs again and again, a psychological
component may compound the problem.
The recurring sleep deprivation will produce
a fear of not falling asleep or waking up and making things even worse.
In short, in a vast majority of cases the problem is both biological
and psychological. The only true remedy is to go to
sleep later and wake up later thus being late for school
(perhaps a lesser evil). The only natural half-remedy is
to measure as precisely as possible the optimum time of going to sleep,
and sticking to that time religiously every day.
That optimum time is the earliest time that roughly
provides 95% or more certainty that sleep latency will be less than
10-15 min.
(i.e. no more than a quarter of an hour of
tossing and turning). Very often, this optimum time will provide for a
mere 3-5 hours of sleep. However, this sleep is most likely to be the
best quality sleep achievable in such conditions. Naturally, affected
individuals will suffer a degree of sleep deprivation on a daily basis.
This is still better than futile tossing and turning, waste of time,
and fitful sleep associated with insomnia. If you suffer from
sleep-onset insomnia, and you suspect it could be caused by a delayed
sleep phase, you could research additional remedies such as morning
sports, strong morning lights, and radical solutions such as ... giving
up electricity after 19:00.
Why do newborns
sleep so much?
(anonymous,
2001)
Question:
Do babies sleep so much because they're learning so much or are they
learning so much because they are getting so much sleep?
Answer:
Babies sleep so much because their brains have been designed to do so
in the first months of their life. They do learn a lot, and learning
does increase the demand for sleep, but this is not the main regulatory
factor. Sleep control systems in babies simply work differently, and
you probably would not be able to make babies sleep less by making them
learn less. On the other hands, long bouts of sleep are used to
reorganize neural networks in the brain. You could probably do a
serious damage by trying to deprive a baby of sleep. In short, sleep
helps learning, learning induces sleep, but the whole sleep sequence is
a direct outcome of a genetically programmed properties of a young
sleep control system.
Free running sleep
may collide with a "normal" lifestyle
(M.B.,
Netherlands, Nov 11, 2010, 01:06:21)
Question:
I am free running my sleep. I had an
appointment at 17:30. I expected to wake up around 15:00 as in the
previous three days. Instead I woke up around 17:00 still a bit tired.
I had to skip my morning routine (meditation, breakfast, supermemo,
etc.). FRS works really well for me. But today sucked. It was really
stressing having to run due to waking up later than expected
Answer:
Free-running
sleep will often produce a phase shift. If you tend to wake up very
late, you will also tend to wake up later each day. This is a hallmark
symptom of delayed sleep phase syndrome (DSPS). DSPS, however
severe, is never a health problem if you can free run your
sleep.
However, it will often cause scheduling problems. You will need to
swing towards one of the two extremes: either make your life less
dependent on meetings and appointments that can collide with your sleep
schedule, or study DSPS remedies that can stabilize your sleeping
phase. Even if you wake up late, waking up always at the same time,
makes scheduling much easier. If you do not opt for one of the above
extremes, you will risk collisions that will make your days, as you
say, "suck". What is even more dangerous, if you disrupt your
sleep
rhythm on a free-running schedule, you can often lose synchrony between
various circadian variables. This will result in a situation in which
for a day or even a few days, you will not be sure of your optimum
sleep time. Even SleepChart may be unable to make a good prediction.
This will inevitably result in poor quality sleep, and a few days of
lower productivity
Solutions for people suffering from DSPS
(Aaron Burtle, , Oct 01, 2009, 23:36:26)
Question:
I recently came across your write up regarding
polyphasic sleep. The idea of sleeping in naps spread throughout the
day intrigued me, as I have always suffered from what I was unable to
properly quantify, but now know is DSPS. If I do not use an alarm
clock, and go to sleep when I become tired, I see my sleep/wake times
shift to significantly later times every day (hours later). This has
been a constant source of frustration for me, and I considered a
polyphasic schedule in order to help correct the problem. However,
after reading "polyphasic sleep: facts and myths", I have decided this
would be a sincere waste of my time. I was wondering if you had any
experience with helping those who have DSPS maintain a more, "normal"
schedule. Is a bi-phasic sleep schedule more suitable for someone with
this sleeping disorder (sleeping from 2-7am with a nap from 1-2pm for
example)? Google has told me that the most common treatments seem to be
rotating ones sleep until they line up with civilized society and then
using something like bright light therapy to keep the clock reset. Will
this be treating the symptoms alone or actually getting at the root
problem? Do you know of any other techniques which could help me
situation?
Answer:
Probably, most of the cases of DSPS can
be explained by a lack of compatibility between the genetically
determined sleep regulatory system, and the lifestyle. You can easily
cure the disorder if you decide to change your lifestyle. However, such
a change is usually not feasible due to the type of employment or
family life conditions. This means that you are probably, for a while,
sentenced to a constant battle with your body clock.
It is true that the best known remedy is to cycle to alignment and reset the cycle. In other words, if possible, use your natural tendency to go to sleep 1-2 hours later, until you align with the desired sleep rhythm. At that point, your battle begins by efforts to provide strong morning resetting stimuli (e.g. bright light, stress, exhausting exercise, etc.). Those can be enhanced by evening measures such as melatonin or the avoidance of light, stimulation, stress, etc. In other words, you need to provide resetting stimuli in the morning, and avoid evening sleep delay factors such as computers, TV, artificial lighting, etc. For most people, a degree of sleep deprivation is more acceptable, than several futile inactive hours in the evening in a dark room.
Using a biphasic sleep like you describe (2-7 am, 1-2pm) is a good idea. However, you must be aware than naps taken too late are likely to delay the sleep phase making matters worse (even though the same naps can be a blessing for your mental performance, alertness and creativity).
Needless to say, polyphasic sleep does not bring any advantage to a DSPS person. In DSPS, you suffer because of a slight misalignment of your main circadian low. Polyphasic sleep disregards the circadian cycle entirely making matters worse. Ad hoc napping (as opposed to planned/artificial "Uberman" napping) is a reasonable way to alleviate sleep deprivation, however, (1) it needs to follow your natural brain needs, (2) it may have a detrimental impact on the cycle itself (often worsening the degree of DSPS).
In conclusion, DSPS epidemic can be considered a civilizational disorder in which the pressure of a modern lifestyle stands in disagreement with millions of years of evolution. In the long run, once we fully understand all biochemical and hormonal processes underlying sleep, it is possible that mild pharmacological intervention will make it possible to regulate the circadian cycle. Currently, this is possible to a degree, but you are bound to experience side effects and research on the matter is still scant.
An expert on TV said clearly that we get
lowest alertness at 8 am, and then it progressively increases. This is
opposite to what you claim!
(anonymous, , Oct 20, 2009, 10:15:29)
Question:
An expert on TV said clearly that we get lowest
alertness at 8 am, and then it progressively increases. This is
opposite to what you claim!
Answer:
Lowest alertness at 8
am might be true for people who go to sleep too late and wake up with
an alarm clock. However, it is definitely not true in free running
sleep. The person who got lowest alertness at 8 am would most likely
keep sleeping till 10-11 am and only then wake up naturally. If you use
SuperMemo and collect your sleep data, you can see clearly on your
alertness graph, that alertness is highest at the beginning of the day
(perhaps starting with the first hour after awakening due to the
transition from sleep to wake that sometimes may take some time). Low
morning alertness can only be explained by the misaligned circadian
rhythm. If circadian lows occurred earlier, morning would be brisk and
alert.
In other words, the expert might be right. Most people wake up too
early and are sleepy throughout the morning. But this is a situation we
should all strive to eliminate by getting sufficient sleep and sleeping
in the optimum hours.
Alertness graphs
show nothing
(Steven
Zhong, China, Jun 10, 2011, 10:10:01)
Question:
In my SuperMemo, Alertness graphs show nothing or show error messages.
Answer:
To see how your alertness changes in the course of the day, you need to
first log in your sleep data. Moreover, you need to make repetitions on
the days you log your sleep. If you have no sleep data, or sleep blocks
are not interspersed with repetition blocks, you will not be able to
see your alertness graphs in SuperMemo.
Sleep timing may be more important than the total amount of sleep
(J. P., Jun 21, 2011, 21:30:51)
Question:
Does one's bedtime have any importance if they
are getting the total amount of sleep his/her body needs? For example
what is the damage, if any, one is doing if he/she changes bedtimes
from 10pm-6am to 3am-11am for work, school, social activity, fear of
vikings, etc?
Answer:
Bedtime may be more important than
the total amout of sleep. You always need to sleep at the time when
your body clock says it is your subjective night. You will get more
benefit from 2-3 hours of sleep at the right time (your night), than
from 8 hours at the wrong time (e.g. when jetlagged in Japan). Note
that it may be hard to get 8 hours during the subjective day without a
serious prior sleep deprivation. If you feel more refreshed after
sleeping 3am-11am, you should use it instead of the "conventional"
10pm-6am. You can also shift your subjective night bracket with
chronotherapy, however, maining those "less natural" hours may require
lots of self-discipline and knowlege, if you are a typical "owl".
Segmented sleep is not your optimum way of sleeping
(Damian Yates, Apr 7, 2013, Sun, 00:15)
Question:
Many websites say that 4 hours of sleep followed by 2 hours of being awake then another 4 hours of sleep us more healthy and say that studies show that people live longer with this method, is this true?
Answer:
No. This is not true (unless this sleep pattern comes naturally). If this was to be your natural pattern, you would have probably discovered it years ago. The sites you mention might be referring to segmented sleep, which is an expression of having "too much time for sleep", e.g. as in long nights without electricity. This type of sleep might be healthy if you can induce it naturally, e.g. by giving up on electricity and all forms of nighttime work or entertainment. However, this may also be a very inefficient way to spend your nights. In natural free running sleep, your nights might be just 5-6 hours long (esp. if you complement that night sleep with a siesta). Natural sleep is always best and it does not need to consume many hours of your day. You can read more about segmented sleep here: http://www.supermemo.com/articles/sleep.htm#Segmented_sleep
Instead of looking for a perfect sleep pattern in literature, learn about free running sleep, and you will soon know what works best for you. Read about free running sleep here: http://www.supermemo.com/articles/sleep.htm#Formula_for_good_sleep
Sleep is not for closing eyes only
(عبدالله ابو محمد, Tue, 19 Feb 2013 00:30:33 +0300)
Question:
In my research, I have concluded that sleep serves only one function: closing the eyes. Loss of consciousness follows only due to boredom. Note that fish that do not have eyelids do not sleep. There is more evidence to prove my thesis.
Answer:
Science says that sleep serves neural function. The body of evidence is huge. You cannot ignore all that evidence and build your own theory based on a couple of observations. You can easily disprove your thesis by mechanically forcing a human being to keep his eyes open (with some irrigation to prevent corneal damage). Sleep will follow inevitably.
That sleep will largely fulfill its function even during daylight (light has a
major impact on sleep phase, not on sleep quality). To begin serious
theorizing, you would need to answer the immediate question: if the function of sleep is to close the eyes, what is the function of closing the eyes?
What is sleepy potion?
(Ëﳿ, Wed, 25 Sep 2013 11:27:46 +0800 (CST))
Question:
I'm reading your article, Good sleep, good learning, good life, and I have a question about it: What actually is the sleepy potion in Clock and Hourglass metaphor? Is that melatonin?
Answer:
Melatonin will correlate well with the concept of the "sleepy potion" as it indeed is primarily released during the subjective night. However, "sleep potion" should have a wider and more precise meaning as "all circadian-based processes that generate consolidated night-time period of high sleep propensity". This will then include melatonin, but will also involve neural processes, e.g. firing in the SCN, etc.
Optimum length of nap in biphasic sleep
(Lucas Zieland, Wed, 24 Jul 2013 11:56:19 +0800)
Question:
I was wondering whether you had an opinion on whether biphasic sleepers should have a 20-30 or 1.5 hour nap? I've heard that taking a 20 minute nap can be sustainable with a 6 hour core sleep, thereby saving an average of 1.7 hours in a day, but don't want to undergo a change to this sleep schedule if it is similarly unnatural or unhealthy
Answer:
The only natural and healthy length of the nap is the length programmed in your brain. This means you should go to sleep at the right time (usually 7-8 hours from natural waking), and wake up naturally. Natural waking may take place in 3 min or in 60 min. In most people, unless they are sleep deprived, siesta rarely lasts longer than 2 hours. You should never think of saving time on sleep because you will likely end up sleeping longer or getting sleep deprived. The shortest healthy sleep you get on well-timed free running sleep.
Sleep deprivation is like smoking: health setbacks are inevitable
(Dominika J, Poland, Jan 25, 2014, Sat, 11:32)
Question:
What is the healthiest method to recover from sleep deprivation for people who have no choice: they need to sleep little and must be in top shape soon after?
Answer:
This question is a good opportunity to smuggle some essential metaphorical knowledge about sleep. People understand their cars better than their own brains. This is why many ask this question without realizing it is analogous to the following:
The analogy should powerfully demonstrate that we need to focus on minimizing situations in which people need to be deprived of the most essential physiological process needed for the health of their brain. The analogy is necessary to emphasize the fact that the function of sleep is little understood and little appreciated in society. Even the medical profession violates the rules of healthy sleep on a regular basis with irrational shiftwork schedules.
Instead of looking for recovery methods, most of sleep deprived people would do much better if they tried to change their lifestyle or habits of people around them. A student should insist that being late for a class might actually make him or her smarter. A nurse should combat a shiftwork schedule that violates basic principles of circadian hygiene where there are much healthier schemes possible. A young mom should consider co-sleeping instead of fighting the baby's and her own natural biological needs.
For those who need to be ready for action at a moment's notice, the best hope comes from recovery sleep on the night that follows one's turn of duty.
The situation in which the brain is regularly deprived of sleep can be compared to a regular withdrawal of oxygen or nutrients. There will be negative neural consequences that will translate to cognitive deficits and the whole gamut of health consequences. In short, there is no sleep deprivation without negative health effects!
Is there a way to minimize damage? As always, healthy lifestyle principles do not change. All remedies like caffeine, sugar, drugs, cold water, social interaction, may bring temporary relief, but may result in more damage in the long run. They can all be tools for flogging the horse that is already dying. Exercise might be better as it will engage different brain centers than those that are involved in more intellectual pursuits. Minimizing intellectual effort would spare the neural resources and possibly reduce the damage. In other words, staying zombified might be a good option. The infamous polyphasic sleep might help if the timing of naps was properly chosen. Polyphasic sleep in conditions of sleep deprivation is highly unpredictable, esp. if irregular sleep is maintained for longer. Naps are a great remedy if taken at the right time. A well timed 20 min. nap could partly compensate for an hour of lost night sleep. However, if a nap launches the full nighttime sleep cycle, it can make things worse by affecting the sleep phase and making further planning only harder. Moreover, if such a nap needs to be interrupted with an alarm, it may bring more damage than benefit. There are a number of devices on the market that promise to optimize the timing of naps, but the complexity of sleep models involved in sleep deprivation and napping is high enough to be skeptical about their usefulness. Predicting the status of the brain using electrical measurements or accelerometers might work for simple situations in a healthy sleep cycle. The complexity of models increases astronomically once perturbations are involved. Simple models assume the synchrony of brain centers involved in sleep. Sleep deprivations and badly timed naps destroy that harmony and superficial measurements may be of little value. Moreover, recovery may be difficult due to the neural chaos that ensues. Long periods of wakefulness, followed by long recovery sleep, combined with sleep phase measurements are the shortest path towards regaining balance. However, in cases of long term abuse, sleep control centers might suffer neural damage and even that healthy brain's recovery algorithm might not work. In short, there is no way around healthy naturally timed sleep cycle as there is no way to drive a car undamaged without tires.
The question is very interesting, but it was born from a wrong approach to sleep and its value. The philosophy of sleep must change on the societal scale!
Sleep onset latency is a good measure of optimum bedtime
(T.S., May 10, 2014, Sat, 21:37)
Question:
As long as I can fall asleep in 20 minutes, what's the difference between being tired or not tired? Why does it matter? I ask because you say:
"Whatever SleepChart tells you about your optimum bedtime, it should only be a rough guidance. Being really tired is the key to determining the actual optimum bedtime".
Answer:
If you can fall asleep fast, it is indeed the best measure of your readiness for sleep. Ideally, you should fall asleep in 3-5 min. 20 min. might indicate you go to sleep a bit early, however, if it never leads to insomnia, 20 min. is ok too.
The term "tired", in this context, refers to sleep propensity, which is a combination of the right circadian timing and strong homeostatic sleepiness (i.e. "mental tiredness"). SleepChart is pretty good at charting your circadian sleep propensity. However, homeostatic "tiredness" depends on many factors that may not be part of SleepChart data. For example, intellectual effort, procedural learning, exercise, stress, etc. If you exerted your brain a lot or exercised a lot, your homeostatic sleepiness will increase and the optimum bedtime will shift to an earlier hour, while your optimum sleep length will increase. The impact of stress will depend on its timing and its nature. Acute stress may have a stronger impact on sleep, while acute stress early in the day may actually improve your sleep or advance your bedtime. When scientists measure the resultant of circadian and homeostatic sleep propensity, they often use multiple sleep latency test (MSLT) to measure sleep onset latency. In other words, time to sleep onset is indeed your best measure for determining the optimum bedtime.
Many a sleep myth come from generalizing personal experience
(Wanda B., Dec 10, 2015)
Question:
I think you are spreading some harmful anti-schooling propaganda with your ideas like "it is better to be late for school than hurt the brain with alarm clock". Kids need to be trained to get up for school early so that they be ready for challenges of adult life. No boss will ever accept an excuse "I am late for work because I needed to protect my brain". My granddaughter gets up very early for swimming pool and then goes to school. She does not need an alarm clock mind you. When she comes back home, she is so tired, she goes to sleep early. The best sleep comes before midnight. It is not a myth like you claim. I know it on my own example as I often have to work till very late. When I get a chance to go to sleep early, I am healthier and I feel better. I am sure late work is unhealthy and should be avoided. This is what kids learn through discipline.
Answer:
Unfortunately, your reasoning carries two problems. For one, you cannot rely on individual experience to generalize for the population. Secondly, your conclusion about best time for sleep is wrong. The best time to sleep is determined not by the clock, but by the "body clock" (i.e. the brain). In your case, this might be the time before midnight. In the case of a teenager, or even a preschooler, this time might come much later. It all depends on the individual circadian cycle. As much as you feel bad when forced to go to sleep later, in reference to your natural hour, the kid will feel worse when she needs to get up earlier. In addition, going to sleep early may simply be impossible, unless the kid suffers serious sleep deprivation from the day before. Most of kids do get into the rhythm by being woken up early on a regular basis. Unfortunately, they also play a visible price, e.g. in the number of infections, and the invisible price in the slowed brain development.
If your granddaughter can get up early without an alarm clock, it only means that her parents made sure she develops healthy habits that require no interference with her circadian biology.
You can read elsewhere at supermemo.com that the brain is not well trainable in terms of resistance to sleep deprivation and the later one begins bad sleep habit routine (e.g. to please the boss), the better.
Fortunately, in the modern world, people who find it difficult to get up in the morning for biological reasons, can find a world of creative pursuits where they can match their lifestyle to their biology.
Because of the lack of tools for diminishing the impact of sleep deprivation
on a child's brain, we oppose "sleep discipline for kids" other than the adherence to healthy sleep habits (which may include getting up early as long as the circadian rhythm is set to match the desired cycle)