Skip to content

Day 2

Sleep Lesson: What Happens in Our Bodies During Sleep?

We all know that we need sleep to live but how exactly does sleep help us? What's even going on when we go to bed every night?


Besides giving us energy for the day, sleep greatly affects our cognitive function abilities. As you learned on Day 1, getting fewer than 7-9 hours of sleep on a regular basis affects your judgment, alertness, and even your memory. In college, you might feel the need to stay up late once in a while, but pulling an all-nighter before an exam is NEVER in your best interest!


Getting enough sleep is also important for your mood and mental health; lack of sleep is related to feelings of stress and anxiety. College can be a stressful time for multiple reasons, whether it’s school, relationships, or living away from home. During sleep, your body produces various hormones that affect your appetite, weight, and immune system. Not getting enough sleep can cause you to overeat, create excess insulin, and can raise your blood pressure.


While some of these are short-term effects, if you routinely do not get the sleep your body needs, the long-term negative results can take a toll on your physical body as well as your mental and emotional state. Our brains are magnificently hard workers, using ¼ of the body's entire energy supply,while accounting for just 2% of the body's mass. They need time and space to rest and repair. In a sense, this is what your brain is doing when you go to bed.


Every cell in our body requires nutrients to fuel it and, as a byproduct, every cell produces waste that the body needs to get rid of. Normally, our bodies use the lymphatic system to process nutrients by taking proteins and other waste from the spaces between the cells and dumping them into the blood to be disposed of. But there are no lymphatic vessels in the brain… so how does this unique organ receive and, perhaps more importantly, rid itself of waste? New research suggests it has to do with sleep!


When we fall asleep, the blood vessels in our brain shrink, allowing cerebral spinal fluid to rush through, capture waste, and dump it back into the blood for the body to dispose of. When the brain is awake, it puts this cleaning mode on hold, just like you and I may put cleaning our house on hold until the weekend.


But just like in your house, if you stop cleaning your kitchen or bathroom for a month, your home will become completely uninhabitable very quickly. But in the brain, the consequences of not cleaning are far greater. The very function of our body is at stake. Sleeping is your body's natural way of cleaning house. The failure of the brain to clear its waste during sleep can contribute to diseases like Alzheimer’s.