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"Why We Sleep" by Dr. Matthew Walker Chapters 1 and 2 Review by David Park

Magic Pill Prevents Illness During Flu Season (WWS Ch. 1 and 2)

If there was a magic supplement that prevents the cold, Alzheimer’s, heart attack, stroke, and mental illness while keeping you fit, happy, and attentive, then everyone would be taking it... Or would they? According to a staggering number of studies, this supplement exists and 97% of young adults in the United States frequently skip their daily dosage of at least 8 hours a night. According to Dr. Matthew Walker, these skipped doses of the magic supplement (sleep) among teenagers is caused by society’s apathy toward sleep from the failure of science to explain why we need it. In his New York Times #1 bestselling book, Walker seeks to report the most accurate knowledge regarding sleep based on modern science.

The purpose of this article is to outline Walker’s most important points from Why We Sleep so you can save time, move on with your life, and perhaps get more sleep. The points that I have listed in this article are the ideas from chapters 1 and 2 that are most applicable to fellow pre-med students.

Chapter 1 To Sleep Society has an apathy toward sleep because the failure of science to explain why we need it, so what happens when we don’t sleep?

1. Lack of sleep: Demolishes your immune system The flu season is approaching us. I’ve already seen a couple students miss class because of illnesses. Sleep rearms your immune system so you can survive the barrage of microbes you face everyday in class.

Destroys the body and mind:

a. Is a key factor determining whether you develop Alzheimer’s b. Increases the likelihood of your coronary arteries becoming blocked c. Sets a path toward cardiovascular disease, stroke, and congestive heart failure d. Contributes to all major psychiatric conditions

Disrupts blood sugar levels and swells concentrations of a hormone that makes you feel hungry. These cause mood and appetite alterations that (1) cause you to gain weight (2) seek food that is high in sugar and low in nutritional value

Why do we sleep? There does not seem to be one major organ within the body or process within the brain that isn’t optimally enhanced by sleep.

For the Brain: a. Enriches our ability to learn, memorize, and make logical decisions b. Recalibrates our emotional brain circuits, allowing us to navigate next- day social and psychological challenges with cool-headed composure c. A consoling neurochemical bath that mollifies painful memories and a virtual reality space in which the brain melds past and present knowledge, inspiring creativity

For the body: a. Restocks the armory of our immune system, helping fight malignancy, preventing infection, and warding off all manner of sickness.

So we don’t get fat: a. Reforms the body’s metabolic state by fine tuning the balance of insulin and circulating glucose. b. Regulates appetite c. Maintains the flourishing microbiome within your gut

In summary, sleep is the single most effective things we can do to reset our brain and body health each day.

Chapter 2: Caffeine, Jet Lag, and Melatonin

This chapter explains the two main functions that determine when you sleep: your circadian rhythm and sleep pressure from adenosine. If you are not interested in how sleep works but rather how this knowledge directly impacts our everyday lives, read part 3!

Part 1: Circadian Rhythm Regulates the timed preferences for eating and drinking, your moods and emotions, the amount of urine you produce your core body temperature, your metabolic rate, the release of numerous hormones, and regulates cycle of arousal.

a. For anyone interested: this was first discovered by Jean-Jacques d’Ortous de Mairan using his plant in the dark experiment, and was later supported by Kleitman and Richardson in their sleeping in mammoth cave experiment. Controlled by suprachiasmatic nucleus: an area in the brain that senses light and releases melatonin, the messenger that helps regulate the timing of sleep.

Part 2: Sleep Pressure

The longer you are awake, the more adenosine will accumulate. a. Adenosine increases your desire to sleep b. It turns down the volume of wake promoting regions in the brain and turns up the dial on sleep inducing regions. c. Caffeine battles adenosine for the same receptor sites. Caffeine, however, does not activate the site but blocks adenosine from binding. Caffeine has a half life of 5 to 7 hours d. Decaffeinated does not be non-caffeinated. One cup of decaf contains 15 to 30 percent of the regular dose in a regular cup of coffee e. For the entire time that caffeine is in your system the sleepiness chemical it blocks (adenosine) nevertheless continues to build up.

Part 3: What does this all mean?

Circadian rhythm: It is a common misconception that a good night’s sleep is getting 9 hours of sleep per night. A more accurate description of good sleep is “8 hours of sleep that follows your circadian rhythm.” For example, it does not matter that you got 9 hours of sleep if you slept in the middle of the day. Your body gets the most out of sleep that follows the appropriate schedule. Sleep pressure: say no to caffeine

How do I know if I’m getting enough sleep? After waking up in the morning, could you fall back asleep at 10 or 11 am? Can you function optimally without caffeine before noon? Do you get at least 8 or 9 hours of sleep? If you didn’t set an alarm clock, would you sleep past that time? Do you find yourself at your computer screen reading and then rereading the same sentence? Do you sometimes forget what color the last few traffic lights while driving?

Wow. That was a lot of information for 2 chapters. A review of the next couple chapters will be found in my forthcoming article on Why We Sleep. See you in a couple weeks.

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