Everybody sleeps. Indeed, there may be nothing more important to wellness than getting good quality sleep. When we don't get enough, virtually every aspect of our health suffers, from our thinking and memory to our immune system and how we feel emotionally. Lack of sleep even makes us more likely to develop more serious diseases. Meanwhile, when we make sleep a priority, we are likely to reap a host of health benefits, including clearer thinking, better mood, a stronger sex drive, and a body that is generally more inclined to run the way it should.
But how many of us really know much about sleep? Many of us take sleep for granted until something goes wrong, or until we find ourselves wearing down. Then we start looking for answers to questions like how much sleep should we get? When should we sleep? Is there anything we can do to make it easier to fall asleep? Fortunately, answering those questions can give us a strong foundation for wellness.
Let's start with the basics.
What is sleep?
After a long day, nothing feels better than a good night's sleep. Your body rests, and your consciousness drifts off into a (hopefully) pleasant dream state. But what else is going on?
Fascinatingly, no one is entirely sure why we need to sleep. But scientists do understand that our time asleep is a chance for our brains to take care of business and clean house. This includes clearing out toxins that build up during the day, and building new neural pathways to process memories.
While we're dreaming, our brains are actually remarkably active. It's like the night crew comes on to work, our conscious minds leave for the day and our brains start vacuuming and mopping up. Specifically, studies have found that our brain activity while we're awake produces toxins that can cause damage to our brain cells over time. However, when we fall asleep, research suggests that the cellular structure of our brains actually changes. The natural gaps between our brain cells widen, allowing cerebrospinal fluid to flow between them, washing away any accumulated toxins.
One study compared this process to a plumbing system for the brain-, one that can only activate while we're asleep.
In addition, scientists believe that sleep is when we lock in or release memories. If we learn something during the day, our brains can solidify that knowledge as a memory later that night, and connect it to other memories, which not only helps us to remember better, but boosts our creativity. Conversely, our brains can also pare away neurons related to memories we no longer need.
The rest of our bodies are also heavily affected by sleep. Like the brain, the other organs of the body do important work during sleep. This includes producing key hormones like sex and growth hormones, repairing damage, and strengthening our immune systems.
Emotionally and psychologically, sleep also provides us with much needed respite. Sleep is an opportunity to let go for a while, and lay down any cares or worries that might be occupying our thoughts.
Stages of sleep
There are two stages of sleep: rapid eye movement (REM) sleep, and non-REM sleep. For most of time that we're sleeping, our bodies are generally calm. Our brain waves, heartbeat and breathing slow down, our body temperature drops, and our muscles relax. This is called non-REM sleep, and is essential to feeling rested the next day.
However, during several discrete periods while we're asleep, everything changes. Our brain activity spikes, our pulse and breathing quickens, and our eyes start darting rapidly back and forth, despite the fact that our eyelids are still closed. This stage, called REM sleep, occurs several times during the night, typically starting about 90 minutes after we first fall asleep. Dreaming mostly happens during REM sleep.
How can I improve my sleep?
If you want to learn more about sleep, it's probably because you want to improve the quality of your sleep (or are wondering how little you can get away with). If you want to support your own wellness, getting enough sleep is one of the simplest ways to do so. There's nothing fancy about it, but it does require commitment and focusing on sleep as a crucial component of your day.
How much sleep is enough?
First, how much sleep is enough? That's an age-old question without one specific answer. Many of us grew up hearing that we should aim for 8 hours a night. Some scientists now say 7-9, others 8-10. Anyone who has been a teenager knows that adolescents need more sleep than average, and doctors now recommend up to 10 hours for children and young adults.
One thing is clear, forcing ourselves to sleep less always comes at a cost that our bodies have to pay.
However, how much sleep we need may not be entirely static. Studies of some of the few communities on earth who still live as hunter-gatherers find that they average between 5-6 hours of sleep a night, all while maintaining higher levels of wellness and fitness than most people living in developed countries. Those who sleep that little in industrialized societies typically see their health plummet. The amount of sleep we require, it seems, may be directly connected to how we live during the day.
The best answer to the question of how much should you sleep? Whatever feels right to you. If you feel rested in the morning, you're probably getting enough sleep. If not, you probably need more! Try turning your alarm off on the weekend, and see how long you sleep before you naturally wake up.
What can I do if I can't sleep or want to sleep better?
Many people struggle with insomnia, or restless, poor quality sleep. While it can be tempting to reach for a sleeping pill, those carry a host of side effects. However, changing your habits around sleep can be an effective, long-term strategy to get more rest.
Sleep experts often suggest starting by setting consistent times to go to bed and wake up. The idea is to get your body on a schedule, so you brain knows when it's time to start winding down for the night. There isn't one particular preferable bedtime, but you want to make sure you're giving yourself enough sleep before you need to get up.
When you do wake up, spend as much time in the morning sun as you can. Exposure to sunlight, especially during the early hours of the day, can reset your circadian rhythm. Take a quick morning walk outdoors or simply open the blinds and stand in front of your window for a few minutes to signal your brain that it is time to start the day. The particular quality of morning sunlight helps your brain to better understand that it's time to awaken, which also helps it to be ready to sleep that night.
Evidence is mounting that screen time: using your phone, computer or television - before bed keeps your brain overstimulated, making it harder to fall asleep. It's a good idea to avoid screens for at least an hour before you go to bed, really, the longer the better. Likewise, many people find that drinking caffeine in the late afternoon or evening keeps their brains too wired to sleep at night. Eating sugar or carbs (which break down into sugar) at night can also have a similar effect.
Instead, if you can, make the hour or two before sleep an opportunity to gently close out the day and prepare to rest. Talking with loved ones, reading a book, meditating or having sex can all help ground you and help your mind slow down. It's a good time to dim the lights or light a candle, drink some camomile tea, or take an epsom salt bath.
There's no one right way to do it, but setting the intention of getting ready for sleep in whatever way you see fit can help.
Brain Basics: Understanding Sleep
National Institutes of Health
Brain May Flush Out Toxins during Sleep
National Institutes of Health
NIH-funded study suggests sleep clears brain of damaging molecules associated with neurodegeneration.
Sleep Expert and Neuroscientist Dr. Matthew Walker on JRE
Notes from a 2-hour Joe Rogan Experience podcast interview with Matthew Walker, chock full of fascinating new science about sleep. (Well worth listening to the podcast, too!)
How to Sleep
James Hamblin for The Atlantic
Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies
Gandhi Yetish, et al
Current Biology, 2015
Matthew Walker, PhD, Why We Sleep: Unlocking the Power of Sleep and Dreams, 2017