What Happens When We Sleep

Every night, nearly everyone on Earth experiences a period of unconsciousness and stillness. However, what exactly occurs within the body during this state of sleep remains a fascinating mystery. Additionally, what are the consequences of insufficient sleep?

Sleep is regulated by your circadian rhythm, or body clock, located in the brain. The body clock responds to light cues, ramping up production of the hormone melatonin at night and switching it off when it senses light.

There are four stages of sleep that the body experiences in cycles throughout the night. On a good night, we cycle through these stages four or five times.

Stages one and two are light sleep. This is a transition from being awake to falling asleep. Heart rate and breathing begin to slow, body temperature falls, and muscles may twitch. Stage three is sometimes referred to as delta sleep because of the slow delta brainwaves that are released during this stage.

This is the first stage of deep sleep, where our cells produce the most growth hormone to service bones and muscles, allowing the body to repair itself.

Stage four is where we begin to dream. The body creates chemicals that render it temporarily paralyzed so that we do not act out our dreams. In this stage, the brain is extremely active and our eyes, although closed, dart back and forth as if we were awake.

Humans roughly spend 1/3 of their lives asleep. Modern lifestyles, stress, and the proliferation of technology mean that people are sleeping far less today than they were a century ago. Sleeping less than seven hours per day is associated with an increased risk of developing chronic conditions, which could reduce life expectancy.

So for a healthier, longer life, get some shuteye.

WHAT IF YOU DON'T SLEEP?

Sleep deprivation Not getting enough sleep won't just make you cranky. It could kill you.

The United Nations even considers sleep deprivation a form of torture. And the longer it lasts, the worse it'll get. Losing sleep affects people differently, but generally the effects increase as the hours do. Just 48 hours without sleep is considered extreme sleep deprivation, but you'll probably get weird before then.

After 18 hours with no sleep, you might feel a little drunk. Staying awake that long is equivalent to having a blood alcohol content of 0.05%, which is what you get with three or four drinks in the span of two hours.

24 Sleepless hours, Less alert that BAC comparison jumps to 0.1%, higher than the legal driving limit in every state. You might feel foggy, less alert, or uncoordinated, almost like you're wearing sleepy beer goggles, including double or blurry vision. That's because sleep deprivation slows down our brain cells' ability to talk to each other.

So if you actually are drinking alcohol, drowsiness can increase its effects. And while caffeine could make you feel more alert for several hours, it'll only work up to a certain point.

By a day and a half, this could all get worse and then some. Your chances of getting sick are higher than usual because your body can't fight like it normally can, and around this time, your brain and body get so tired that you start experiencing microsleeps, tiny periods of sleep, maybe around 30 seconds, that you might not even notice. Definitely annoying and even dangerous if you're doing something like driving a car. And then there's the potential for hallucinations. Visual distortions are most common. Your water bottle grows to twice its size or moves around the room. But you could also experience sensational or auditory hallucinations, things like feeling someone who's not there tap you on the shoulder or hearing your name being called.

Once you hit 48 hours, it's literal torture, which is why extreme-sleep-deprivation studies are now prohibited by law in most countries. Two days without sleep can cause you to start losing your grip on reality. Hallucinations worsen, and you might even undergo depersonalization. That's the feeling that reality is slipping away, which may or may not include an out-of-body experience.

Tack on extreme anxiety, irritability, stress, and fatigue, and it's no wonder the UN doesn't allow this kind of deprivation. After 72 hours, you're not gonna be able to think about anything but hitting the hay.

According to one study, you need four days to recover from losing a single hour of sleep. Try getting to bed early instead of sleeping in late, or, better yet, avoid the recovery period entirely by getting seven to eight hours of sleep every night in the first place.

"Your future depends on your dreams, so go to sleep." – Mesut Barazany