I’m definitely guilty of skimping on my own sleep, always thinking to myself “what’s one or two nights really going to hurt?”. But it turns out sleep deprivation adds up...
Sleep is a necessary function in the body, and getting quality sleep, getting enough of it, and during the proper times are factors nearly as important as food and water to the human body. Considering you’ll spend almost a third of your life sleeping (if you’re doing it correctly), it’s important to know what not getting enough sleep can do to you.
How is Each Body System Affected By Poor Sleep?
Central Nervous System:
This is the information highway of your body, and sleep keeps it functioning properly. But, eventually sleep deprivation builds up. This negatively effects how the body sends information. Without enough proper sleep the brain can’t form or maintain pathways to learn and create new memories. It also becomes harder to concentrate and response time decreases. 
During proper sleep pathways form between neurons in the brain to help you remember new information. Without this the brain becomes exhausted and unable to function. The signals the body sends throughout become delayed, leading to decreased coordination, compromised decision-making, and creativity. This can also lead to (if sleep deprivation becomes extreme):
-hallucinations -impulsive behaviour -depression
-paranoia -suicidal thoughts -microsleeps
Microsleeps are intermittent moments of sleep lasting only a few seconds in duration. They are completely out of your control, and are especially dangerous if driving, working, or moving about. 
While you sleep, your body produces protective, infection-fighting substances such as cytokines. These substances protect against outside invaders like bacteria and viruses. They also help you sleep, improving your ability to defend yourself, and increasing energy. 
Sleep deprivation prevents this process from occurring, and can increase the rate of infection, decrease your immune function, and increase the total time it takes to recover from an illness or infection. Long-term sleep deprivation can increase your chances of developing a chronic illness like diabetes or heart disease, and getting less than 6 hours of sleep per night actually increases the rate of early death by up to 12%. 
Your sleep is responsible for regulating the levels of two important hormones in your digestive system. Leptin, which tells the brain that the stomach is full and stops you from overeating, is decreased due to sleep deprivation. Ghrelin increases your appetite, and can be increased when you don’t get enough sleep. These together increase the chances that you will overeat at night, and can actually lower your metabolism, causing you to store more calories as fat. 
Insulin release after eating is also increased by sleep deprivation. This is particularly bad due to the fact that over time this increased presence of insulin can lead to insulin resistance, and eventually Type 2 Diabetes. 
Another important function of healthy sleep is to keep the heart and blood vessels in good working order, and to regulate blood sugar, blood pressure, and inflammation levels in the circulatory system. These are all vital to heal the heart and blood vessels from any negative symptoms that may occur over time. There is also a correlation between sleep deprivation and an increase in the risk of cardiovascular disease, heart attacks, and strokes over time. , 
Hormone production is also reliant on sleep. In fact, testosterone production requires 3 hours of uninterrupted sleep. Sleep deprivation also negatively affects growth hormone production, especially in children and adolescents, which is why it’s very important for them to get as much sleep as they need. It also prevents the building of muscle mass and the repairing of cells and tissues. 
Cortisol (stress hormone) is also released by the body if you have a poor sleep. Not only influencing how you deal with stress, this hormone actually increases how many of your consumed calories will end up being stored as fat. 
How Do We Improve Our Sleep?
There are actually quite a few ways to improve your sleep quality. They’re all fairly straightforward and easy to remember…
Firstly, it’s important to set a routine before bed. Your body develops a sleep rhythm known as the Circadian Rhythm, that it follows daily. This rhythm is a combination of several contributing factors, but one of the major ones is the time that you consistently go to bed and wake up at. Even if you have a late night, it is healthiest for your Circadian Rhythm to get up at the same time as you normally would. 
Second is to ensure you don’t have caffeine or alcohol near your bed time (most suggestions say within 6 hours). These are for different reasons. The caffeine is an obvious one, as even if you do manage to go to sleep, your brain doesn’t, and will wake you up and ensure a restless sleep. The alcohol on the other hand is a bit more deceptive. You may feel as though you sleep better after a ‘nightcap’, but this is actually only partially true. You do fall asleep more easily, but while you’re asleep your body is preoccupied with processing the alcohol in it’s system, and won’t allow your brain to go into the most restful parts of it’s sleep. In the long term this is actually equivalent to sleep deprivation. 
Our third suggestion is to keep electronics out of your bedroom. Most handheld electronics, computers, and televisions emit blue light. Blue light mimics sunlight to your brain, causing you to remain alert and awake much later than you should. This confuses your internal body clock and can lead to poor sleep. 
Fourthly, is to sleep in a cold room. It doesn’t have to be freezing, but your body’s core temperature actually needs to drop several degrees before it can go to sleep. This is why it’s always much easier to sleep in a room that’s too cold, as compared to a room that’s too hot. 
Our last suggestion for improving sleep is to set up a scene that you associate with sleep. Using white noise or earplugs are great for sleeping in a room that’s too loud or quiet. Sleep in familiar surroundings is always of a higher quality, and therefore setting up a familiar, comfortable scene night after night can help to improve sleep quality. 
Don’t let yourself get stressed out about your sleep. If you worry, it definitely makes it harder to get into that restful state. Even though it’s a natural function that we’re all born with, learning healthy sleep practices, and unlearning the unhealthy ones can be a long and arduous process. But, don’t worry, it’s easier to get back to healthy sleep than it is to get to unhealthy sleep, just take it step by step and you’ll get there.
1. Effects of Sleep Deprivation
2. Understanding Sleep
3. Effects of One Night of Sleep Loss