You and I can’t begin to have a serious conversation about your health, especially on trying to improve it through nutrition and exercise, without first talking about sleep. Sleep is at the base of our health pyramid at RxFIT. “The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise,” says neuroscientist Matthew Walker. Let’s not ignore the facts, you and I are “socially, organizationally, economically, physically, behaviorally, nutritionally, linguistically, cognitively, and emotionally dependent on sleep.” Without it, we die — literally.
The basis for our view on sleep at RxFIT comes from this scientist and professor from the University of California, Berkeley. For additional readings beyond this article, we recommend Walker’s book Why We Sleep: Unlocking the Power of Sleep and Dreams.
Before going too far into depth, I’d like to repeat what I said yesterday. The tendency is always to make health more complicated than it needs to be. Sleep is no different. If you don’t take anything from this blog post, it should be this: Go to bed and wake up at the same time everyday. If you do this, don’t worry about anything else.
Journalist Michael Pollan coined the term “Nutritionism” after years of research into diets to mean the “sum of all of a food’s parts.” He criticized that by focusing on one macronutrient or disregarding another food group not only makes eating and cooking more complicated, but is just wrong all together. In harmony with Pollan’s word, sleep is no different. You can’t focus in on one aspect of sleep and evangelize it – people have been sleeping for centuries, so we don’t need to complicate it. Below, I’ll lay out the importances of and explain what happens during each sleep stage and then address what your sleep quantity and quality should look like.
Stages of Sleep
Matthew Walker writes in his book, “No one type of sleep is more essential than another. Losing out on any one of these types of sleep will cause brain impairment.” So let’s take a shallow dive into each:
- Wake Sleep: You’re somewhat conscious of what’s going on around you, even though you are asleep. This usually happens around six times a night. There is not much research to indicate the purpose of wake sleep, but we know it is necessary.
- REM Sleep: Also known as your “dream sleep,” REM is where you are delusionally conscious to the world around you. Your muscles are totally paralyzed (think of when you carried a child to bed at night from the couch and their body was totally limp). This stage is usually seen as most beneficial to your mental health as neural connections are being strengthened (memory consolidation and dreaming). On average, REM sleep takes up about 20% of your sleep.
- NREM Sleep: Research has shown that we have four additional stages of NREM sleep, which have been called Stage 1, Stage 2, Stage 3, and Stage 4.
- Stage 1 and 2 (“Light Sleep”) account for roughly 50% of your total sleep time. The primary purpose here is to transition you between REM and SWS sleep.
- Stages 3 and 4 (“Slow-Wave Sleep”) account for 25-30% of total sleep time. The Slow-Wave Sleep (SWS) is a very active and intense phase of sleep. While in SWS, your body will repair and regenerate tissues, build bones and muscles, and strengthen the immune system.
I believe it’s important to note that you get most of your SWS sleep in the first four hours of the night – it’s like your brain is a parent to the body, making sure everything is taken care of before taking care of itself. After NREM is complete, your brain then transitions REM sleep for the next four hours.
What’s fascinating about this, however, is that your body is extremely rhythmatic. Your brain actually has a clock (circadian rhythm) and knows when you’re planning on going to bed and waking up the next day (due to past sleep schedules). So, if you go to bed later at night than you usually do, your brain will spend less time in NREM sleep because it knows it still needs to get REM before waking up. This will negatively affect how your body recovers – particularly your bones and muscles. Conversely, if you shorten the other end of your sleep by waking up earlier than normal, you cut yourself short of REM sleep. This will negatively affect your memory and other cognitive functions. So, what should your sleep quantity and quality look like?
Sleep Quantity and Quality
With everything in regards to health, you need both a healthy dose of the right quantity and quality.
You should be sleeping at least eight hours every night. If you don’t believe it, take Matthew Walker’s research over the past 30 years:
“The recycle rate of a human being is around sixteen hours. After sixteen hours of being awake, the brain begins to fail. Humans need more than seven hours of sleep each night to maintain cognitive performance. For example, after ten days of just seven hours of sleep, the brain is as dysfunctional as it would be after going without sleep for twenty-four hours.”
Sleeping less than eight hours causes the following to happen:
- Time to physical exhaustion drops by 10-30 percent.
- Aerobic output is significantly reduced.
- Similar impairments are observed in your body’s ability to produce power (lift, move, jump, etc.).
- Decreases in peak and sustained muscle strength.
- Impairments in cardiovascular, metabolic, and respiratory capabilities. For example:
- Faster rates of lactic acid buildup (you get more sore, faster – and the soreness lasts longer).
- Reductions in blood oxygen saturation.
- Converse increases in blood carbon dioxide because of a reduction in the amount of air the lungs can expire.
- The body’s ability to cool itself through sweat.
- Risk of injury (and I mean a significant risk of injury). For example:
- On seven hours of sleep (instead of eight), you are 25% more likely to get injured during exercise.
- On six hours of sleep, you are 40% more likely to get injured.
Simply put, there is so much that eight hours of sleep a night can do that medicine simply cannot.
“Sleep consistency” and “sleep regularity” are two phrases used interchangeably in academic research. Both mean to say the body’s consistent routine of going to bed and waking up at the same time everyday.
In June of 2017, Harvard University introduced this novel concept by controlling 61 student’s sleep schedules and then measuring their GPA (grade-point-average). Harvard reported a positive correlation between sleep consistency and academic performance. More specifically, students that stuck to the same bedtime and wake-time everyday had an average GPA of 3.72, while students who slept just as much (but no consistent bedtime/wake-time schedule) had a GPA of 3.24. That’s an entire letter grade difference! To put that in perspective, that’s a significant difference in salary of a student landing a job.
Other studies indicate the same findings, some even arguing that going to bed and waking up at the same time is more important than getting the recommended eight hours of sleep per night. Again, the purpose of this post isn’t to argue what is most important – but to simply inform that sleep is important.
Go to bed early and consistently so your body will be invigorated (it needs the SWS sleep within the NREM stage). Then, wake up at the same time everyday after a full night of sleep so your mind will be also invigorated (it needs the REM stage). Some may even recognize this as scripture.
As a wrap-up, I reiterate what I said in the beginning. Simply, go to bed and wake up at the same time each day. Take Walker’s advice over my own:
As creatures of habit, people have a hard time adjusting to changes in sleep patterns. Sleeping later on weekends won’t fully make up for a lack of sleep during the week and will make it harder to wake up early on Monday morning. Set an alarm for bedtime. Often we set an alarm for when it’s time to wake up but fail to do so for when it’s time to go to sleep.
If you’re serious about improving your health, let’s first address your sleep habits.