I never thought much about the importance of sleep until I was introduced to the book “Why We Sleep” by Mathew Walker, PhD. Actually I first read about the notion of getting 8 hours of sleep in the book “Presence” by Amy Cuddy, which simply touches the surface, while “Why We Sleep” goes behind the curtain and explains in great detail why we need much more sleep than we think. Like many of you I thought sleep was just the opposite of being awake with little purpose but to rest.

Why We Sleep unlocks the power of sleep and dreams. The author takes you on a journey from the evolution of sleep (apes to humans, birds, etc.), the stages of sleep, clinical studies, and its associations with various diseases & disorders. As you can see the book covers a lot, therefore for simplicity & impact, I will only focus on the basic mechanics of sleep and its effects on human health. I will cover the other topics of sleep in a later blog. I’ve also provided recommendations / tips on how to get a good nights sleep.

What’s the big deal?

Two thirds of adults throughout all developed nations fail to obtain the recommended eight hours of sleep nightly. The less you sleep, the shorter your life span.

Studies have linked sleep to our ability to learn, create memories, and solve problems. Sleep has also been tied to mood. Without enough sleep, a person has trouble focusing, and responding quickly — a potentially dangerous combination, such as when driving. In addition, mounting evidence links a chronic lack of sleep with an increased risk for developing obesity, diabetes, cardiovascular disease, and infections. [1]

Human beings are the only species that will deliberately deprive themselves of sleep without legitimate gain. The World Health Organization (WHO) has declared a sleep loss epidemic throughout the industrialized nations. It is no coincidence that countries where sleep time has declined most dramatically over the past century, such as the US, the UK, Japan, and South Korea, and several in western Europe, are also those suffering the greatest increase in rates of the mentioned physical diseases and mental disorders. [2]

Consequences of sleeping less than six or seven hours a night:

  • Compromises your immune system – more than doubling your risk of cancer.
  • Determines whether or not you’ll develop Alzheimer’s disease.
  • Disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic.
  • Coronary arteries become blocked & brittle, leading to cardiovascular disease, stroke, and congestive heart failure.
  • Contributes to all major psychiatric conditions, including depression, anxiety, & suicidality.
  • Increase concentrations of a hormone that creates hunger leading to unwanted weight gain (obesity).
  • Inability to learn & retain / recall knowledge (memory) effectively.
  • Poor physical performance (athletes, etc.).
  • One person dies in a traffic accident every hour in the United States due to fatigue – related error. Vehicular accidents caused by drowsy driving exceed those caused by alcohol and drugs combined.
  • Higher risk of stumbling, falling, & breaking bones for the elderly during nighttime visits to the bathroom (due to fragmented sleep).

Overall, any individual, no matter what age, will exhibit physical ailments, mental health instability, reduced alertness, and impaired memory if their sleep is chronically disrupted.

The Mechanics of Sleep:

Before we go further its important you understand what causes the phenomenon of sleep. There a two main factors that determine whether you want to sleep or want to stay awake. One is an internal twenty four hour clock located within your brain. The clock creates a cycling, day night rhythm that makes you feel tired or alert at regular times of night and day, respectively. The other factor is a chemical substance that builds and creates a “sleep pressure”. The longer you’ve been awake, the more the chemical pressure accumulates, and consequently, the sleepier you feel. It is the balance between these two factors that determines how alert you are during the day and how well you sleep at night.

Many people have heard about “Melatonin” as a sleep aid. This chemical generated by the pineal gland within the brain sends a signal that tells the body its night time. Melatonin helps regulate the timing of when to sleep by systematically signaling darkness in the body. But melatonin has little influence on the generation of sleep itself. Melatonin simply provides the official instruction to commence the event of sleep, but not participate in the sleep event itself. Melatonin is not a powerful sleeping aid in and of itself, at least not for healthy, non-jet lagged individuals. [3]

Sleep Pressure & Caffeine:

As you are reading this, a chemical called “adenosine” is building up in your brain. It will continue to increase in concentration with every waking minute that elapses. As the adenosine increases so does your desire to sleep. This is known as “sleep pressure”.

You can artificially mute the sleep signal of adenosine by using a chemical that makes you feel more alert – “Caffeine”. It is the most widely used psychoactive stimulant in the world. Caffeine effectively inactivates the receptor sites that adenosine would normally latch onto, acting as a masking agent. By occupying these receptors, caffeine blocks the sleepiness signal, normally communicated to the brain by adenosine. Caffeine tricks you into feeling alert and awake, despite the high levels of adenosine that would otherwise seduce you into sleep.

Levels of circulating caffeine peak approximately thirty minutes after oral administration. Caffeine has an average half-life (ability of the body to remove 50% of a drug) of five to seven hours.

Caffeine which is not only prevalent in coffee, certain teas, energy drinks, dark chocolate, ice cream, as well as drugs such as weight loss pills and pain relievers – is one of the most common culprits that keep people from falling asleep easily, typically masquerading as insomnia (an actual medical condition).

Caffeine also increases the release of catechol amines (such as adrenaline) via the sympathetic nervous system, which among other things can make your heart beat faster, send more blood to your muscles and tell your liver to release sugar into the bloodstream for energy. [4]

Also be aware de-caffeinated does not mean non-caffeinated. One cup of decaf usually contains 15 to 30 % of the dose of a regular cup of coffee. [5]


All of us will experience difficulty sleeping every now and then, which may last just one night or several. This is normal. However, if you have difficulties falling asleep, waking up in the middle of the night, waking up too early in the morning, difficulty falling back to sleep after waking up, and feeling nonrefreshed throughout the day – lasting several months, then you may have chronic insomnia. If so, then the author suggests you seek out a sleep medicine doctor.

While the reasons are unclear, insomnia is almost twice as common in women. African Americans and Hispanic Americans suffer higher rates of insomnia than Caucasian Americans. These stats have important implications for well recognized health disparities in these communities, such as diabetes, obesity, and cardiovascular disease, which have known links to a lack of sleep.

What is stopping you from sleeping?

The author claims there a five key factors that are inhibiting our ability to get a sound restorative sleep.

  • Constant Electric Light as well as light emitting diodes (LED).

    • Artificial light halts the forward progress of biological clock that is normally signaled by the evening surge in melatonin.
    • Blue LED (laptop screens) – Has twice the impact as light from light bulbs on melatonin.
  • Regularized Temperature
    • A bedroom temperature of around 65 degrees Fahrenheit (18.3 C) is ideal for most people.
  • Caffeine
  • Alcohol
    • A powerful suppressor of Rapid Eye Movement Sleep (REM). The body metabolizes alcohol into chemical byproducts called aldehydes and ketones. The aldehydes block the brains ability to generate REM sleep.
    • Alcohol also causes fragmented sleep – frequent brief awakenings – leading to non-restorative sleep.
  • Legacy of punching Time Cards
    • Enforced awakening with alarm clocks
    • A study showed that participants artificially wrenched from sleep will suffer a spike in blood pressure and a shock acceleration in heart rate caused by an explosive burst of activity from the fight or flight part of the nervous system. [6]

Your diet also appears to have some impact on your nighttime sleep, besides caffeine & alcohol. There is limited research on diet and its effects on sleep. Eating a high carbohydrate, low fat diet for two days decreases the amount of dreamless sleep (Non Rapid Eye Movement – NREM), but increases the amount of REM sleep dreaming. In a carefully controlled study of healthy adult individuals, a four-day diet high in sugar and other carbohydrates, but low in fiber, resulted in less deep NREM sleep and more awakenings at night. [7]

Dangers of sleeping pills:

There are no sleeping medications on the market that induce natural sleep. Sleeping pills target the same part of the brain as alcohol does. They are part of the same class of drugs known as sedatives. There are over fifteen studies from different groups around the world showing higher rates of mortality in those who use sleeping pills. Dr. Daniel Kripke, a physician at the University of California, San Diego, discovered that individuals using prescription sleep medication are significantly more likely to die and develop cancer than those who do not. [8]

Other consequences of sleeping pills:

  • Increase risk of fatal car accidents.
  • Higher risks for falls at night, particularly the elderly.
  • Higher rates of heart disease & stroke.
  • Individuals taking sleeping pills were 30 to 40 % more likely to develop cancer within the two and a half year period of the study than those who were not.

Twelve tips for healthy sleep (National Institute of Health – NIH): [9]

  1. Stick to a sleep schedule – Go to bed and wake up at the same time each day, even though it involves an alarm clock.
  2. Exercise – No later than two to three hours before bed.
  3. Avoid Caffeine & Nicotine – Effects of caffeine can take up to 8 hours to wear off.
  4. Avoid Alcoholic drinks before bed – Even though it relaxes you, it prevents you from reaching REM sleep, keeping you in lighter stages of sleep.
  5. Avoid large meals and beverages late at night – A light snack is okay.
  6. Avoid medicines that delay or disrupt sleep – examples are prescribed heart, blood pressure, asthma medications, as well as herbal remedies for coughs, colds, or allergies.
  7. Don’t take naps after 3 PM – Naps can help make up for lost sleep. Too late can make it difficult to fall asleep.
  8. Relax before bed – Reading a book or listening to music.
  9. Take a hot bath before bed – The drop in body temperature after you get out may help you feel sleepy.
  10. Dark bedroom, cool bedroom, gadget free bedroom – No TV, cell phone, or computer.
  11. Have the right sunlight exposure – Sleep experts recommend that, if you have difficulties falling asleep, you should get a full hour exposure to morning sunlight, and at night turn down the lights before bedtime.
  12. Don’t lie in bed awake – Get up and do something relaxing until you feel sleepy.

The author states that one of the most important takeaways from his book is that humans can never “sleep back” that which we have previously lost.

***One more note for parents and or expecting mothers – Published in Dr. Lewis Terman (psychologist) papers and book Genetic Studies of Genius, Terman found that no matter what the age, the longer a child slept, the more intellectually gifted they were.


  1. https://www.nia.nih.gov/health/good-nights-sleep
  2. Sleepless in America, National Geographic, http://channel.nationalgeographic.com/sleepless-in-america/episodes/sleepless-in-america/
  3. A. Erland and P.K. Saxena, “Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content”, Journal of Clinical Sleep Medicine 2017;13(2):275-81
  4. Ask The Professor: Why does caffeine give you energy? http://tuftsjournal.tufts.edu/2009/03_1/professor/01/
  5. Genetics of caffeine consumption and responses to caffeine: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242593/
  6. Kaida, K. Ogawa, M. Hayashi, and T. Hori, “Self-awakening prevents acute rise in blood pressure and heart rate at the time of awakening in elderly people, “Industrial Health 43, no. 1 (January 2005): 179-85
  7. P. St-Onge, A. Roberts, A. Shechter, and A.R. Choudhury, “Fiber and saturated fat are associated with sleep arousals and slow wave sleep, “Journal of Clinical Sleep Medicine 12 (2016): 19-24
  8. F. Kripke, R. D. Langer, and L.E. Kline, “Hypnotics’ association with mortality or cancer: a match cohort study,” BMJ Open 2, no. 1 (2012): e000850. The Dark Side of Sleeping Pills: http://darksideofsleepingpills.com/
  9. https://medlineplus.gov/magazine/issues/summer12/articles/summer12pg20.html

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