Revision 4 (2018-10-27)


Always go to sleep at the exact point when you are sleepy (when your body, not your plan needs), have a constant 24-hour-period well-timed schedule of activities and ensure nothing disrupts your sleep (not even an alarm clock!). Your sleep habit is healthy, if you fall asleep in 5 minutes and wake up suddenly and clear-headed. The main function of sleep is for optimizing memories and brain housekeeping, not for brain or body resting. You cannot get more sleep and store it for later. The primary enemy of sleep is stress, eliminate the source of it’s existence, don’t try to escape it. The other enemies are lack of exercise, lack of learning, alcohol, recreational drugs and sleeping pills. Drink coffee only immediately after awakening. Don’t smoke. Read the original summary here.

Modelling sleepiness

There are only two components. Sleepiness is maximum, when both of them are in the optimum state - strongest homeostatic and fastest ascending circadian. For more details about the physiology of sleep, read here.

Circadian component is cyclical. Each cycle is approximately a bit longer than 24 hours. The circadian sleepiness is the ability to maintain sleep. Clock metaphor is useful in explaining the circadian component. In every clock cycle, there is only one optimum state - a moment when a sleepy potion is released. You can detect it by feeling the suddenly increased drowsiness of your body. If you have irregular sleep hours or have a lot of stress, you may not feel the sleepy potion. To change your cycle length, or to entrain it to exactly 24 hours, you need to expose yourself more intensely to zeitgebers (any external cues that your body can receive) that occur with 24 hour periodicity. The strongest zeitgeber is light. Reception of light as a zeitgeber is diminished if you are blind or short-sighted. Other examples of zeitgebers can be: diet and substance intake, relaxing or stressful physical or mental activity, temperature, humidity, sound, smell, touch.

Homeostatic component is stronger the longer you stay awake, the more you learn, think and do intellectual work. It is weaker the more caffeine, stressful physical or mental activities you have. Alcohol and marijuana makes this component stronger, but take them sparingly due to damage to health and sleep depth. Melatonin also makes this component stronger and it does little damage, but only if it is prescribed by an expert - used only in extreme cases, timed and dosed well. The homeostatic sleepiness is the ability to initiate sleep. It is a result of mental effort. Hourglass metaphor is useful in explaining the homeostatic component. When you wake up, the hourglass is full. With every mental effort, it becomes less and less full. The optimum state is when the hourglass is empty. Here are examples of ineffective or harmful ways to try to initiate sleep earlier: counting sheep, yoga, aromatherapy, acupuncture, chamomile, massage, magnesium, meditation, warm bath, being in a quiet room, performing rituals, drinking cup of tea, cocoa or milk, eating turkey. These are only examples of relaxing activities. Other examples of ineffective or harmful methods are: accumulating sleep debt, consuming sleeping pills, avoiding naps and caffeine.

Timing the nap

If you feel sleepy during your awake time, you should take a nap, but only if it is earlier than the midpoint.

Timing the work

These optimums apply if we define work as a stressful activity. Optimum for mental work is when homeostatic sleepiness is lowest and circadian is fastest descending - there are two points in one circadian cycle: first is after awakening, second is after mid-point of your awake time. Optimum for physical work is after awakening for delayed sleep phase syndrom people and before sleeping for advanced sleep phase syndrom people. Read this section about stress - how much is too much and how to reduce it.

Timing the play

This optimum applies if we define play as a relaxing activity. Optimum is in the evening. It should be full of effortless physical rest and mental entertainment.

Timing any activity

First of all, work has to transition into play gradually - meaning the most stressful work has to be done when you begin working. Any activity is timed well if it doing it feels fun and will not disrupt the upcoming activities and does not conflict with the 24-hour-period zeitgeber system, or is part of. Rest and entertainment is fun after a productive day. Mental work is fun when brain is ready. Sleep is fun when your body is ready. Eating is fun, but the expectation to sleep soon is disrupted, if food is hard to digest or is energizing, because instead of being relaxed, it is lit-up with digesting it and storing the unused energy.

If you want to shift your 24-hour cycle to begin earlier, then intensify the zeitgeber system - have harder exercise and more lights in the morning, harder and more focused work hours, more boring and relaxing play in the evening, etc. If you want it to begin later, then remove or even flip the order of the zeitgebers - relaxation in the morning, stress in the evening. In conclusion, shifting circadian sleepiness needs temporary changes in actions that affect homeostatic sleepiness.

Maximizing sleep quality

It is a myth that humans have a tendency to sleep excessively. The main idea of a quality sleep is letting it run free. Rules, by priority:

  • Get into bed exactly whenever you feel sleepy (when you are sure you will fall asleep within 20 minutes) - it means you must never fight sleepiness, you sometimes will wait well above your expected time - do not try to fall asleep every day at the same time or set any other forced time
  • Stick to a constant 24-hour-period plan, which includes the timing of work, play, other activities and the remaining zeitgebers.
  • Be sure nothing, except your body, influences you while you sleep - that means that no zeitgebers must occur, until your own body wakes you up - for example never using an alarm clock, always isolating from noise and light (if needed, even using unintrusive ear plugs or eye masks), always sleeping alone (except when the partner acts more like a zeitgeber than an alarm clock), etc.

Reducing stress

Read here for more details about the rules:

  • simplify the day-to-day, slow down, eliminate interruption, refuse more often and delegate
  • do creative work that is useful to other people
  • set and follow goals in all areas - work, family, exercise, etc.
  • have a good process of getting things done or getting rid of things that cannot be done
  • dump tasks from your head to task list, prioritize it and execute by priority
  • measure how much you have accomplished during the day
  • work on your overall contentment of the world
  • avoid conflict, be nice and make other people smile
  • destroy relationships with people that cause stress
  • build relationships with people that relieve stress
  • re-learn the joy of being in nature
  • exercise
  • have a healthy sleep


Morning exercise has positive effect - it will make you fall asleep faster and make the sleep deeper. Intense exercise late in the day will have the opposite effect. However, a relaxing exercise late in the day can have positive effect by amplifying the homeostatic sleep drive. It is possible to have relaxing body building, sex, calisthenics, yoga, stretching, etc. It must be performed in accordance with your zeitgeber schedule, for example low light, silent, low temperature etc. Read more here.

Revision 3 (2018-01-28)

Start with a video by Matthew Walker - Why We Sleep.

Then you can read the Sleep Smarter and The Power of When books and/or watch their corresponding videos:

The goal of sleep hygiene is to avoid mistakes of not acting in accordance with your biological circadian rhythm. In the order of decreasing importance:

  1. not setting aside 7-9 hours just for sleep (with late stimulating activities and early alarm clocks)
  2. allowing noise and light during your sleep
  3. getting too hot or cold during sleeping - not adjusting your socks, pyjamas, covers and room temperature
  4. going to sleep and having meals at different times each day
  5. receiving too much artificial light after the sunset
  6. receiving too little sunlight during the day, especially right after waking up
  7. stressing your mind and body in the evening, instead of the morning
  8. napping and consuming caffeine or nicotine
  9. drinking alcohol and lots of liquids 4 hours before sleep
  10. not having a glass of water right after waking up
  11. not having a nutrient rich, low carbohydrate diet
  12. using your bed for anything other than sex or sleep

The first four mistakes are the direct physical reasons of a bad sleep. But they are non-negotiable items to ensure about your bed time.

The 5th, 6th, 7th and 8th mistakes are which you must also start understanding. Either you plan your day time to avoid them or you will wake up groggy, no matter the duration you were asleep.

Avoiding the last four mistakes is also proven to improve your sleep.

Revision 2 (2016-09-17)

During the whole day (between waking up and getting to sleep):

  • do recurring activities everyday at the same time, most important ones are wake up, meal and going to bed times
  • do not use the bed
  • make sure the bed matress is neither too soft, nor too hard
  • make sure the bedroom receives as much sunlight as possible
  • receive as much fresh air and sunlight as possible
  • set aside 8h for purely sleep time
  • do not consume stimulating substances (i.e. caffeine, nicotine, etc.)
  • do not sleep or nap
  • begin the day with only stimulating activities, gradually transform into doing calming activities, and end only with them
  • do not avoid planned daytime activities, even if feeling tired
  • if working 8h in an office, do at least 10min break outside (e.g. go buy groceries for lunch)

After wake up:

  • wake up
  • immediately #1: get sunlight (e.g. open curtains, go outside)
  • immediately #2: go get a glass of water (e.g. from the tap, bottle, well)
  • immediately #3: have at least 10min exercise
  • immediately #4: have breakfast

Before sleep:

  • as early as possible: ventilate the bedroom with at most 21°C fresh air (e.g. turn on AC, open all windows)
  • at least 5h before sleep: have at least 10min exercise
  • after 18:00: take as little foods or fluids as possible
  • after 18:00: receive as little light as possible (e.g. bathroom lights, electronic screens)
  • just before #5: write a journal entry
  • just before #4: prepare the clothes and other things for tomorrow
  • just before #3: make the bedroom as dark as possible (or wear eyemask)
  • just before #2: make the bedroom as silent as possible (or wear earplugs)
  • just before #1: get into bed on the back without a pillow, with socks and covers (or also pyjamas) that surely get you warm and cozy
  • just before #0: if not feeling sleepy, then relax: have sex, read a book or meditate (e.g. deep breathing and listening, or Headspace -> Singles -> On-the-go -> Sleep #2 meditation, or direct the mind to the body, think about how it feels, think through the day from start to finish in 30s, scan the body from bottom to top, all the time switching off the muscles, start counting down from 1000)
  • sleep

Revision 1 (2013-10-31)

This is my personal, unprofessional, work-in-progress review of various laymen literature about improving sleep, the most important activity.

Sleep hygiene is a collection of habits that help you to have a good night’s sleep. Most bodily processes (such as temperature and brain states) are synchronised to this internal 24-hour physiological clock, called “circadian rhythm”. The goal of sleep hygiene is to stabilize the circadian rhythm.


  1. Sleep in a bedroom that feels restful (dark, quiet) and comfortable (not too soft and not too hard bed matress softness, a cool air temperature, enough blankets to stay warm) is hygienic.
  2. Go to bed, when feeling tired and sleepy.
  3. Get enough sleep - sleep until you wake up without an external cause.
  4. Have a strict routine - work, exercising, meals, drugs, chores, other activities and sleep.
  5. Maximise your time being exposed to sunlight.
  6. Make your mind associate bedroom place with sleeping activity.
  7. Do not drink liquids before bedtime, otherwise you will wake up during the night to go to toilet.
  8. Physically and spiritually relax before bedtime.
  9. Do not fall asleep at daytime.
  10. Address the causes of sleeping problems, not the symptoms.
  11. Exercise every day, first when melatonin secretion stops and second when the greatest cardiovascular efficiency is.

Advice for requirements implementation

  1. Go to bed and get up at the same time every day. (4)
  2. Invest in a mattress that is neither too hard nor too soft. (1)
  3. If you can’t control noise (such as barking dogs or loud neighbours), buy a pair of earplugs. (1)
  4. Use your bedroom only for sleeping. (6)
  5. Do not use sleeping pills. (9, 10)
  6. Begin your day with only stimulating activities, gradually transform into doing calming activities, and end only with them. (2, 5, 8)
  7. Don’t take naps. (9)
  8. Do not use an alarm clock. (3)
  9. Use heavy curtains, blackout shades or eyemask to block out early morning light and any lights during the night. (1, 3)
  10. Do not avoid planned daytime activities, even if feeling tired. (2, 4, 5)
  11. If lying awake (for 20 minutes, if not morning), leave bed. If not morning, then do a calming activity in another dark and quiet room. (2, 6)
  12. Exercise on the first (before breakfast) and the third (90 minutes after dinner) quarter of every day. (11)
  13. If you tend to take your problems to bed, try writing them down—and then putting them aside. (8)
  14. Do office breaks in direct sunlight. (5)
  15. The first thing to do after getting up - raise curtains to let in the morning sunlight. (5)
  16. Don’t sleep with pets or children. (1)

Calming (Boring) activities

  1. Consciously relaxing and stretching every part of your body, starting with your toes and working up to your scalp.
  2. Thinking of a restful scene.
  3. Concentrating on the rhythmic rise and fall of your breathing.
  4. Focusing on a mantra (repeating a word or phrase constantly).
  5. Eating a light and mild snack with amino acids (especially tryptophan and complex carbohydrates (oligosaccarides, polysaccharides).
  6. Sitting quietly on the couch with the lights off and a cup of caffeine-free tea.
  7. Reading something boring, like a telephone book.
  8. Joga.
  9. Deep breathing.
  10. Listening to a relaxing audio.

Stimulating (Interesting) activities

  1. Working mentally (includes thinking about problems, including sleep).
  2. Working physically (exercising).
  3. Using stimulant (cigarettes), caffeinated (some teas, coffee, cola, chocolate) and depressant (alcohol) drugs.
  4. Looking at the clock.
  5. Eating heavy and spicy meals with fatty acids.
  6. Watching LCD, CRT, LED, projector and other displays.
  7. Reading something interesting, like a good book.
  8. Listening to an engaging audio.

Caffeine-free teas

  1. Peppermint.
  2. Chamomile.
  3. Ginger.
  4. Red rooibos.
  5. Mint.
  6. Lemongrass.
  7. Hops.
  8. Lemon balm (melissa).

Final remarks

  • Sleepiness is only when your eyelids are drooooping.
  • Common sleeping problems (such as insomnia) are often caused by bad sleep hygiene reinforced over years or even decades.
  • Sleepiness is associated with a drop in body temperature.
  • Doing a two-week course of writing a sleep diary with how the requirements are fullfilled can be useful in getting the right facts about your sleep.
  • Carbohydrates are not essential nutrients, because they can by synthesized from amino acids and fatty acids.
  • Do not eat simple carbohydrates (sugar) - monosaccharides, disaccharides - at all.
  • Eat more vitamins and dietary minerals.
  • Sleep inducers include tryptophan, valerian.
  • Tryptophan works by increasing the amount of serotonin, a natural sedative, in the brain.
  • Carbohydrates facilitate the entry of tryptophan into the brain.
  • Vitamin B6 helps convert tryptophan to serotonin.
  • A hormone produced by the brain, melatonin is instrumental in regulating the body’s sleep-wake cycle.
  • Light is important for the body to produce melatonin which is a sleep promoting substance.
  • Sunlight early in the day is particularly helpful in synchronising your body clock.
  • Warm hands and feet are particularly important.