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Ah, sleep. No matter how hard we try, we can never seem to get as much of it as we know we’re supposed to.

Experts say 7 to 9 hours per night is the sweet spot — and while this sounds easy enough in theory, the reality is that life (work, errands, happy hour, family time) can easily get in the way of that necessary shut-eye.

If you’re typically sleeping more like 6 hours a night and then rolling into work with a venti cold brew and a pound of under-eye concealer… oof. We feel you, and we’ve been there too.

To understand why sleep is so important, it’s helpful to know the different stages of sleep and what exactly they’re doing for your health. After all, sleep is more than just a luxury — it plays a crucial role in helping your body function at its best.

And not all sleep is quality sleep, either. Your daily habits can make a big difference in helping you get adequate rest, even if you can’t always sleep as many hours as you’d like.

During the night, your body cycles through four stages of sleep. Think of them like levels in a video game — they all build off each other, and you need one to progress to the next.

You’ll typically pass through all four stages three or four times in several hours. Your sleep doesn’t get deeper throughout the night but rather moves between deeper and lighter stages (which may explain why you wake up more easily at certain times).

Stages one to three are known as non-rapid eye movement (NREM) sleep, and the fourth stage is called rapid eye movement (REM) sleep. Here’s how they work together.

Stage 1 (N1)

During those first 10 minutes when you’re drifting off (after you’ve managed to calm down your brain and forget about tomorrow’s to-do list), your body is transitioning between its waking state and sleeping state.

Your mind relaxes, your breathing slows, and your muscles sometimes twitch. If your phone buzzes or a dog barks outside during this sleep stage, you’re likely to wake up for a minute or two before dozing off again.

Stage 2 (N2)

In the second stage, you progress to a deeper and more relaxed sleep. This lasts for 30 to 60 minutes, and it’s the point at which you may start to experience slow-wave brain activity, which indicates the beginnings of deep and restful sleep.

Stage 3 (N3)

By now, your body has reached the deep sleep stage, where it stays for 20 to 40 minutes.

This is the level of sleep you need to feel truly refreshed the next morning, and it only happens once you’ve progressed through the first two stages. It’s also known as slow wave sleep or delta sleep because of the brain activity that occurs.

Your brain waves slow way down and are less responsive to external noises and interruptions. If you’ve ever slept through your alarm or had a short nap turn into multiple hours, you can probably blame it on deep sleep.

REM sleep

Here’s where things get really interesting. REM sleep falls into a different category than the other stages because of what’s happening in your body. In this super deep phase of sleep, your muscles are paralyzed while your eyes move rapidly behind your eyelids.

Your brain actually becomes more active during REM sleep, and many people have vivid dreams in this stage. Your heart rate and breathing speed up. Your body typically goes into REM sleep about 90 minutes after you fall asleep, and it can last for up to an hour.

Interestingly, babies and children spend more time in REM sleep than adults do. Babies are in REM for about half the total time they’re asleep, while adults spend 20 to 25 percent of sleeping time in REM (about 2 hours of an 8-hour night).

You can’t reach deep sleep without experiencing the lighter stages first, which is why doctors recommend at least 7 uninterrupted hours of shut-eye per night. That gives your body time to complete multiple sleep cycles with several hours of deep sleep in the mix.

So, what exactly does deep sleep do? The short answer is “everything.” It contributes to your physical and mental health in invaluable ways.

Here are just a few:

  • It helps your brain store new memories from the day.
  • It gives your mind a much-needed rest from working.
  • It regulates your hormones. Hello, clear skin!
  • It strengthens your immune system.
  • It keeps your blood sugar down and helps control your weight.
  • In the long term, it minimizes your likelihood of developing a chronic disease.
  • It makes you feel way happier the next day.

Basically, sleep allows you to keep functioning like a boss. Too many people underestimate its importance, but it’s actually the real MVP when it comes to living a productive, healthy life.

Even if you’re taking steps in other areas to get healthier, like watching what you eat or exercising regularly, you won’t reap the full benefits of these practices unless you’re also sleeping well.

OK, now that we’ve convinced you to focus on your sleep, here are some tips to help you do just that.

By paying close attention to your daily routine, you can identify the causes of your poor sleep and work to build more positive habits. You don’t have to give up cold brew entirely, but maybe you’ll come to need it a little less.

Set a bedtime (and a wake-up time)

Routines can help your body understand when it’s time to get going and when it’s time to fall asleep each night. They can also help you avoid the temptation to watch that one extra episode of “Succession” before turning off the lights.

To account for the time it takes to fall asleep, set aside at least 8 hours and 30 minutes before your morning alarm.

Try not to nap

If you’re super sleep-deprived and really need a quick power nap, go for it. But be careful not to sleep so much during the day that it keeps you from sleeping a full night.

Avoid screens before bed

You knew we had to bring this one up. Blue light exposure in the after-dark hours can mess with your circadian rhythms.

Put your phone and laptop away at least an hour before bed (or earlier if you can) and try reading a book by lamplight instead. This can be a difficult adjustment at first, but with time, you may grow to love your new reading practice.

Eat a high fiber, low fat dinner

Healthy fats are great for you, but not necessarily in the evenings. Research has shown that eating large amounts of fat in the evenings can prevent your body from getting the deep sleep it needs.

Opt for fibrous foods, including lots of vegetables, and save the avocado for your morning smoothie.

If you can’t sleep, take some deep breaths

Everyone has nights when they can’t fall asleep for hours. Sleeplessness is no fun, but it’s also not the end of the world. Rather than lie awake feeling anxious, practice deep breathing and remind yourself that the worst-case scenario really isn’t that bad.

tl;dr

  • During the night, your body cycles through four stages of sleep, and they build on one another.
  • Stages 1 and 2 are light stages where your heart rate starts to slow. Stage 3 happens almost an hour after you doze off, and this is when you really start to get deep sleep. REM sleep is the stage where you’ll do most of your dreaming.
  • The longer you sleep at once, the more time you’ll spend in deep sleep. Seven to 9 hours per night is the ideal amount for most adults.
  • Sleep helps you retain memories, regulate hormones, manage your blood sugar, and prevent chronic disease.
  • To improve your sleep, try setting a strict bedtime, avoiding screens before bed, and eating high fiber, low fat foods for dinner.