Updated: Feb 14
This is the third of four posts covering the four pillars of healthspan and longevity:
In the last 20 years, we have learned more about the importance of sleep than in the last century. We know now the value of a good night’s sleep and it is not just a luxury—it is a necessity for optimal health and longevity.
Sleep is critical for immune function, metabolic health, and lowering the risk of chronic disease including cancer and dementia. The challenge of getting eight hours of sleep each night runs directly counter to the western lifestyle of constant stimulation and common routines of burning the candle at both ends.
The Five Stages of Sleep
The first step to understanding the importance of sleep is understanding what happens when you sleep and how we look at it scientifically.
Sleep can be divided into five stages:
Stages one and two. These are considered lighter sleep, when you may have some intermittent movement. In stage two, eye movements slow or stop and brain wave activity slows.
Stages three and four. These are considered deep sleep when delta waves predominate in your brain. It is difficult to arouse people from deep sleep—this is also when children experience bedwetting, night terrors, and sleepwalking.
Stage five. This is also called REM sleep and commonly known as the dream stage.
For those who are interested in learning more about the stages of sleep, I highly recommend Matthew Walker’s book Why We Sleep.
Your body has a pattern to these stages. Classically they occur in 90-minute cycles although that varies from person to person and is dependent on many other variables. The typical pattern is more deep sleep in the early part of the night and more REM sleep in the latter part of the night.
Herein lays a significant issue. For those of us who get less than seven hours of sleep, you are robbing yourself of more of your REM sleep. Some may comment: so what, I get fewer dreams?
The problem with robbing yourself of REM sleep is that each stage of sleep has an important purpose. While you spend the majority of the night in stage two, the deeper sleep (stages three and four) has been shown to have a restorative function for the body. Neuroscientist Jeff Iliff explains precisely how this works in a great Ted Talk:
Your body uses REM sleep to repair cellular damage, including muscle. REM sleep is also when growth hormone is released in children and young adults. It is a time of downregulation of your emotional control centers.
Finally, deep sleep seems to serve as a time when your memories from the day are sorted and parsed. Those determined as critical (considering we experience thousands of images, sounds, and smells daily) are placed into long-term memory. REM sleep seems to be critical for further memory consolidation and connection of abstract concepts. It may be where learning is reinforced and encoded.
How much sleep is enough?
The magic number for sleep is eight hours. Multiple studies (including here and here) have shown that getting less than six hours of sleep has significant impacts on academic performance and overall health. So much for pulling that all-nighter for your high school or college final.
The more worrisome data is around physical and mental health. One night of poor sleep reduces your immune function by directly impairing T-Helper cells, a critical part of your immune system. Getting a poor night’s sleep may also reduce your body's ability to mount an immune response from vaccination. That of course is critically important during these pandemic times.
To be clear: we all have nights where we get a poor night’s sleep. These negative consequences are cumulative. They occur when you consistently have less than optimal sleep over long periods of time.
Risks from long-term lack of sleep
Long-term lack of sleep affects the balance of glucose and insulin, lowering insulin sensitivity (a bad thing) and making weight control more difficult. Think of the last time you had little sleep and your desire right when you woke up to have something to eat immediately. That is related to the release of the hormone ghrelin, the so-called "hunger hormone."
Long-term lack of sleep also raises inflammation in your body and has been linked to increased rates of heart disease and cancer. Short sleep duration has been associated with a greater risk of colon polyps. Other research has tied reduced sleep duration to a higher likelihood of stomach cancer and found potential correlations with Non-Hodgkin Lymphoma, as well as cancers of the thyroid, bladder, head, and neck.
None of those studies are good news! My point in listing the above is to emphasize the critical role of sleep in your overall health and well-being. Sleep is not just a luxury.
Bottom line: get eight hours of sleep every night
The good news is there are concrete steps you can take to improve your physical performance, mental resiliency and lower your risk of chronic disease.
Some of you may have heard or read about the term "biohacking." There are many authors claiming the ability to biohack health through various shortcuts. Some of the data are compelling. Unfortunately, when it comes to sleep there is no way to biohack your way out of the optimal eight hours a night.
Improving "Sleep Hygiene"
Strategies to improve your sleep hygiene fall into three broad categories:
Things we do prior to the night that affect our sleep
How we prepare for the "glide path" to sleep
The physical environment where we sleep
Things we do prior to sleep can have a dramatic impact on our ability to get a good night’s sleep
Chemicals such as caffeine and alcohol can dramatically worsen our ability to get to bed or to stay asleep. Caffeine has a half-life (how long until half a quantity of a substance is broken down in your body) of six hours. This means that an afternoon cup of coffee is still significantly in your system when you are trying to get to sleep.
Caffeine impacts the release of melatonin, one of the hormones that tell your body it is time to sleep. Caffeine also acts as a stimulant, the whole reason you take it in the first place. Avoid caffeine after noon. Some people (I am one of them) are very sensitive to caffeine due to how it is metabolized in your body.
Alcohol is a sleep disruptor, period. Most people know alcohol can make you sleepy. But it is also well documented to disrupt both deep sleep as well as REM sleep. Avoid any alcohol at least four hours prior to bedtime.
Exercise and movement are great. Just don’t do it close to bedtime. Leave at least four hours of time prior to going to bed to allow your body to recover. Allow the normal surge in heart rate and hormones like adrenalin and cortisol to subside in time before getting into bed.
Preparing for the "glide path" to sleep
Think of an airplane descending to land. There is a checklist every pilot follows every time in order to ensure they land safely. It is the same with your nightly sleep routine. This glide path starts with what we mentioned above and expands upon it in specific areas.
Wind down at the end of the day by lowering ambient light levels and avoid screens one hour before bedtime. Ambient light suppresses the release of melatonin. Screens, such as televisions, laptops, or smartphones, emit blue light, which stimulates the brain to release dopamine as well as suppresses the release of melatonin.
Do not eat at least three hours prior to bedtime. Eating close to bedtime causes your body to be focused on digestion expending energy to metabolize that meal instead of preparing to rest. The three-hour window improves your blood sugar control (lowers insulin resistance) and reduces levels of C Reactive Protein, a key marker for inflammation.
I’ve saved the best for last. Set a going to bed time and keep it the same time every night. If you know that you need to wake up at 6:30 to start your day then you need to be in bed by 10:30. Set your alarm for 9:30 to allow yourself time to wind down, brush your teeth, and turn off all electronics.
The physical environment where we sleep
Our human ancestors lived in caves for the safety and protection of the tribe. Most men still desire to build their "man cave." Your bedroom should be a reflection of that ancient desire for safety with the comfort of the 21st Century incorporated into your sleep space.
Your bed should only be for two things; sleeping and having sex. It is not the place to watch TV, work on your laptop, or scroll through your phone. These activities should be verboten. The physical act of getting in bed should be a signal to your body that it is time to rest (or that other activity). Your bed should be a sanctuary. Treat it as such.
Set the mood, including light-blocking shades on the windows and keeping the room a few degrees cooler than normal to coincide with your normal body temperature drop as it prepares for sleep. 65 degrees is considered an ideal temperature for sleep.
If you are going to follow one simple rule, it would be to charge your phones away from your bed. It is too much of a temptation to just check or email or social media just one more time or tap the screen if you happen to wake up in the middle of the night. Admit it, you know it’s true! This is especially critical for teens (and sadly pre-teens) who now commonly have a device attached to them at all times.
There are other things you can do to prepare for sleep, such as a cup of herbal tea and certain supplements like melatonin or magnesium, among others. Before using any supplements, however, first I urge you to follow the above steps.
Finally, what happens on those rare occasions when you either can’t get to sleep or wake up and are unable to get back to sleep? First, don’t worry, it happens to everyone from time to time. Do not clock watch (another reason not to have your phone next to your bed). After 10 minutes, get out of bed. Grab a book—a real book. Try some meditation or deep breathing exercises to relax. Now would also be a good time for that cup of herbal tea.
At Dignity Integrative Health and Wellness, we focus on sleep as one of the Four Pillars of health. We are happy to tailor a program to improve your health and longevity. Sleep well!