You know the drill: plenty of sleep equals happy mornings. But what exactly do you know about the architecture of your nightly slumber? Did you know R.E.M. is actually an acronym? Or that you could wake up more refreshed if you set your alarm 30 minutes earlier? And what the heck is sleep debt? We investigate.
While your body sleeps, your brain remains active, it needs time to recharge and catch up after being depleted throughout the day. Just like charging your cell's battery, if you don't sleep enough at night, you won't receive a full charge before you need to start all over again.
The average adult needs between 7.5 and 9 hours of sleep every night. If you're regularly getting less, you've probably accumulated what's known as a "sleep debt." The hours of sleep you don't give your body don't just disappear. If you don't make up for lost sleep quickly, that time adds up. Ever feel like you just pulled an all nighter, even after a full night's rest? That's your pesky sleep debt, asking to be repaid. Think of hours like dollar bills that you owe every night. If you're a few bucks short one night, even if you pay in full the next night, you're still in the red.
Sleep deprivation shows up in lots of ways you may not realize : your mood, your metabolism, your immunity and even your concentration. But chances are you know very little about what happens when you close your eyes. You've probably heard of R.E.M. sleep, but, though it's the most commonly known sleep terminology, it's not actually the deepest sleep you experience throughout the night. R.E.M actually stands for "Rapid Eye Movement" which is when you dream.
Your body will cycle through many levels of sleep several times during a night. First, you transition into sleep during stage 1. Then, light sleep (stage 2) slows your body and lasts around 15-30 minutes until you fall into deep sleep (stage 3) where your brain waves slow and your muscles get some extra blood flow to strengthen them. Finally, roughly 90-minutes after falling asleep, you enter R.E.M. sleep where your eyes move, your breathing becomes shallow and your heart rate and blood pressure increase. Moving through this 90 minute cycle 4-6 times during a typical night creates a chart resembling a city skyline which lead to the term sleep architecture.
This Wikipedia image shows how sleep cycles do in fact resemble a city skyline.
Not only does it matter that you get enough sleep, but also which sleep cycle you're in when you wake up. Timing your alarm to wake you when you're in a lighter stage of sleep will significantly affect how easy it will be to get up. Trying to wake up out of deep sleep will make you feel groggy — it's simply too far to climb. Even if it means waking up a little earlier, think about this chart and consider learning to time your wake-ups to ease out of sleep gently using your body's natural rhythms.
Now, stop reading and get to bed already! Nightly night.