Sleep Quality Over Quantity: How to Know If You’re Getting the Right Kind of Sleep

Getting the recommended eight hours of sleep every night doesn’t mean it’s the quality sleep your brain and body need. If you’re still tired or dizzy after waking up, it could be a sign that you’re not getting the quality sleep you should be getting.

Fortunately, it’s now easier than ever to quantify how good or bad our sleep patterns are. Smart beds, sleep trackers and wearables such as wristbands and rings can help us track and monitor our sleep. Every morning you can view your heart rate, breathing and sleep graphs with information about how much light, deep and REM sleep you got the night before. But all that data is only useful if you know what it means and what you are aiming for.

Here’s how to decode your sleep cycles to get the most out of your shut-eye.

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What are sleep cycles?

People sleep in cycles. The best known is REM, which stands for Rapid Eye Movement, because your eyes move quickly during this sleep phase. Scientists and researchers generally divide the cycles into two broad categories: non-REM And REM sleep. I’m going to split non-REM sleep into two categories that are commonly used by sleep trackers.

Light sleep

Light sleep is the start of your sleep cycle and the way your body rests. Breathing, heart rate and muscle changes prepare your body for the deeper sleep to come.

Light sleep is divided into phases 1 and 2. The first phase is simply the transition from wakefulness to sleep. It makes up less than 3% of your nighttime sleep cycles.

Phase 2 is where light sleep goes to work. When you are completely asleep, your brain activity slows down, but there are bursts of electrical activity. Neuroscience research suggests that these bursts of electrical activity are a crucial part of your brain’s process of transferring information from short-term to long-term memory. That’s why many scientists agree sleeping after studying or learning new material can help you retain information more quickly.

Most people spend more time in Stage 2 than any other stage during long periods of sleep, and that’s a good thing because it’s such an important part of brain health and emotional processing.

Read more: Light sleeper? 4 reasons why and 5 ways to sleep better

Deep sleep

Deep sleep is often confused with REM sleep, but in reality the two are different. Deep sleep is the part of your sleep cycle where your body recovers from the day. During deep sleep, your body secretes growth hormones related to cellular repair and rebuilding.

When you get enough deep sleep, you wake up rested. If you don’t have enough of it, you will feel tired even if you have had a full night’s sleep.

Typically, you will see deep sleep on your sleep tracking devices in the first half of your night. It happens in relatively long segments as your heart rate and breathing slow to their lowest levels. You need about 1.5 to 2 hours of deep sleep every night.

This is also the stage of sleep when it is most difficult to wake up. Deep sleep is just as important as REM when it comes to physical rest, so keep an eye on this phase when monitoring your sleep patterns.

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REM sleep

Maybe the most famous of sleep cycles, REM sleep is interesting and almost science fiction-like. Most people experience REM sleep about 90 minutes after falling asleep.

REM sleep goes even deeper into the recovery of the brain, dreaming and the processing of memories and emotions. This is the sleep phase where your eyes move quickly. If you’ve ever caught your dog or cat in REM, you’ll recognize the eyes darting back and forth.

Your brain waves in REM sleep are closer to wakefulness than in deep sleep, and your breathing becomes irregular and accelerated. Blood pressure and heart rate also rise to near-awake levels during REM sleep.

It’s no surprise that with so much near-awakeness, this stage is when you dream the most.

Fun fact: During REM sleep, your arm and leg muscles are temporarily paralyzed by two brain chemicals, preventing you from physically acting out your dreams, like accidentally hitting your partner instead of that alien villain.

Why it matters

Of course, you can follow in the footsteps of countless generations before us: fall asleep without any trackers and just trust Mother Nature. I encourage this approach, especially if analyzing large amounts of data about your body doesn’t give you peace of mind.

But if you’re interested in sleep data, understanding and correlating how you feel and how well you progress through the stages of sleep can help you make informed decisions about your bedroom environment or schedule.

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