Sleep: the Overlooked Factor that could be Quietly Stealing your Health
Updated: Feb 7
We all do it. In fact, we spend about 1/3 of our lives doing it. Most people say they don’t get enough of it and most know that too little is bad for them. What is it? Sleep.
Sleep is just beginning to gain traction in “mainstream medicine” as the importance of getting a lot of quality sleep is becoming more clear every day (and night). Lack of sleep has been shown to play a role in chronic pain, heart disease, diabetes, obesity, brain disorders, and much more. Fortunately, we also know more about the environmental factors that can help you get a good night’s sleep and sleep technologies that can tell us what “types” of sleep we are experiencing.
Let’s explore what sleep is and why we do it, the difference between sleep cycles, how sleep affects our overall health, and tips to help ensure a good night’s sleep.
Disclaimer: Sleep is an insanely huge topic with new research coming out every day. I’ve provided a good overview below, however there is much more that can be said about sleep and health.
What is sleep?
Sleep is essentially a period of time when the conscious (aware) brain gives it’s control to the un(sub)conscious brain. I like to think of it as our body’s “innate intelligence” taking-over for a period of time every day to repair, replenish, and reboot the whole system (our bodies) after which time our conscious brain takes control and we go back to living our lives, and often re-damaging our bodies. Good thing we sleep, huh?
One sleep cycle lasts about an hour-and-a-half and consists of roughly 4 different sleep stages with different activities taking place in each. A normal 8-hour night sleep contains 4 - 6 sleep cycles. Of that 8-hours, roughly 75% will be spent in Non-REM sleep and 25% in REM sleep. More on that later. Below is a picture illustrating the different stages of sleep. We will come back to this later as we make sense of what is going on in the diagram. At this point, simply notice the organized nature of the cycles with their ups and downs. Also notice how the last-half of the night is spent more in REM (the dark line in the graph) and Stage-2 sleep. This will be important as we move forward.
Stage-1 (Non-REM 1) (N1)
On average it should take 10-20 minutes to fall asleep.
If you full asleep as soon as your head hits the pillow or you lie awake for hours before getting to bed, it can indicate something more serious going on.
The first stage of sleep is essentially very light sleep and should comprise less than 5% of total sleep. This is a transitional sleep between an awake and sleep state where your muscles relax and your brain-waves began to change. It is common to experience a “falling sensation” or “awake-dreams” in this stage.
Tips for this stage of sleep: Your body’s internal clock (called your circadian rhythm) likes routine. Try and get to bed at the same time every night. Keep your bedroom very dark. Light activates the “awake” portion of your brain, especially “blue-lights” which electronic devices emit including TV’s, cell phones, and computers. Any bright light before bed will immediately suppress natural melatonin release making it more difficult to fall asleep, so use dimmers when possible. Keep your bedroom cool (~65-68 degrees). Your body temperature drops significantly at night and it does this by dumping-heat into your pillow, mattress, sheets, and room. Keeping the room cool helps avoid overheating. Also, avoid exercising or eating 1-hour before bed as that can increase body temperature and delay sleep. Diets high in protein and complex-carbs have been shown to help with asleep. Keep your room at a constant noise level. If you have noisy neighbors, live near an airport, or sleep next to a loud sleeper, I recommend sleeping with a fan or some other background noise. It’s less about the overall amount of noise than the noise fluctuations. Avoid drinking more than 3 caffeinated beverages a day as it takes about 7-hours for your body to decrease blood-caffeine levels by half. Avoid any caffeine after 3pm.
Stage-2 (Non-REM 2) (N2)
In a normal sleep cycle, stage-2 or “real sleep” directly follows stage-1. In this stage you are still in relatively light sleep and can be easily woken so controlling and creating a comfortable environment is important. Roughly half of an 8-hour sleep cycle will be spent in stage-2 sleep and this is where motor and implicit learning happens. Neurons in your brain (brain cells) repeatedly fire creating connections with other parts of the brain. The more these cells fire, the better you remember and learn.
This is one of the reasons why research has shown that getting a good night’s sleep right after studying for a test or practicing playing the piano increases performance the next day. This is a bit of a "life hack" for students studying for a big exam and athletes trying to maximize their workout and recovery.
Tips for this stage of sleep: Since you spend roughly half the night in this light-sleep stage, comfort and environment is very important. This includes having a comfortable pillow, mattress, fabric, and position, limiting the number of times you have to go to the bathroom, cool room temperature, constant noise volume, no light, and no PETS! I won’t go into all the various pillow and mattress options here other than to recommend shopping-around and investing in quality. People that wake-up frequently throughout the night usually do so in this stage of sleep from one of the factors listed above. This is also the stage where pain and discomfort will keep you from gaining a more restful night’s sleep.
Pain killers inhibit restful sleep which has been shown to cause more pain the next day. Instead, utilize other methods for pain maintenance including chiropractic, natural supplements, and acupuncture.
Stage-3 (Non-REM 3) (N3) [for simplicity…Delta Sleep is included here]
Stage-3 is also called “deep sleep” because it’s usually very difficult to fully-wake someone from deep sleep. In this stage of sleep, heart rate, blood pressure, and breathing rate all drop. Your body is focused entirely on building, repairing, and detoxifying. Growth Hormone, responsible for tissue repair and growth, immune function, and metabolism, is secreted and more abstract types of learning are reinforced. Prolactin is also secreted which helps build muscle and detoxify the body. This is the stage where your body is restored (think athletes, trauma and injury, chemical and emotional stress). If you’re in a state of high anxiety or do a lot of exercise you will stay in this phase longer as your body needs extra-time with healing.
Tips for this stage of sleep: This is an extremely important sleep phase. Caffeine limits the body’s ability to enter and stay in this phase of sleep. Limit intake. None after 3pm.
Stage-4 (REM Sleep) (Dream State Sleep)
If stage-3 (deep sleep) is all about rebuilding and restoring the body, stage-4 (REM sleep) is all about rebuilding and restoring the brain. In REM sleep, brain activity is at the highest point of the day requiring 50% more oxygen then when awake. This stage of sleep is involved in creativity, logic, long-term memory, and morality. This is where “a-ha!” moments and dreams occur. Recently, we’ve learned that brain detoxification via brain and spinal lymphatics occurs here which may explain associations between Alzheimers and Dementia and loss of REM sleep. The important thing to remember here is that the amount of time spent in REM sleep increases significantly with every passing cycle so half of your REM sleep may occur in the last hour before you wake. That’s why every hour counts when it comes to sleep.
Tips for this stage of sleep: We want healthy brains!
Alcohol interferes with the body’s ability to enter and remain in REM sleep, especially right before bed. This can be a major problem for those who like to enjoy an evening cocktail or glass of wine every night to relax or fall asleep.
Almost all pain medications also interfere with REM sleep. Loss of REM sleep decreases pain tolerance. This is one of the reasons why opioids can be extremely addictive.
What about naps?
Naps aren’t needed in a healthy sleep cycle however we’ve all had days when nothing sounds better than a nap. Early afternoon is usually the best time of day. A 20-minute minute “power nap” has been shown to increase attention and awareness. This is because most of that time is spent in stage-2 sleep where motor learning occurs. A “power nap” after a workout, practice, or studying/learning a new skill can be great to help with learning. Otherwise, a 90 minute full sleep cycle is recommended.
Note on Melatonin.
Many people take melatonin in supplement form to help them fall asleep. I personally do NOT recommend frequent melatonin release for the following reasons. First, melatonin dosages in supplements have been found to be wildly inconsistent and often present at much higher dosages than are found naturally in the body. Secondly, melatonin is a hormone... and whenever you directly supplement with a hormone it instantly affects natural hormone release of whatever you're supplementing PLUS other hormone levels that respond to that hormone. In other words, it can have unanticipated and unwanted side-effects. Rather than melatonin, I recommend magnesium glycinate supplements or chamomile tea, in addition to proper sleep hygiene, to help people fall asleep.
What about shift-work?
Shift-work is currently described by the World Health Organization as a “possible carcinogen” due to its link to increased rates of cancer. Shift workers usually have low-levels of Vitamin D and suppressed levels of melatonin, a hormone involved in helping you sleep. If possible, change shifts or find another job that doesn’t involve shift-work. Obviously, not everyone has that luxury. The next best thing for these workers is to try and stay on the same sleep schedule on weekends and when they aren’t working, monitor vitamin D and melatonin levels, and utilize the general sleep tips provided throughout this article. If possible, avoid harsh artificial lights at work and throughout the day as these suppress melatonin.
The Modern Epidemic of Chronic Sleep Loss
One hundred years ago Americans slept an average of 9.5 hours a night. Today that number is closer to 6.7 hours, a 25% decrease in total sleep. Add up those hours for the whole year and that’s 110 nights of loss sleep a year!
How do you think that is affecting our health? We already know that not enough or poor quality sleep is linked to heart disease, brain disorders, type-2 diabetes, obesity, increased feelings of stress, lower pain tolerance, and hormone imbalances.
So where do we go from here? The good news is that for most people, sleep is a controlled activity. The biggest reason that we sleep less today is because we have more things to distract us (TV, computers, skype, nightlife), we are exposed to increased levels of light (especially blue-light form electronics) and stress, and the ubiquitous use of alarm-clocks (when was the last time you woke up naturally?). We need to make sleep a priority.
Research shows the average person needs about 8.3 hours of sleep a night so that’s what we should shoot for. Less than 7-hours has been shown to significantly affect immune health so that’s a minimum.
If you're interested in learning even more about sleep, you can read more here.
So next time your athlete, scholar, or musician complains about their bedtime, remind them that sleeping might just make them run harder, learn better, and play faster. Just remember to get some for yourself too.