What Happens to Your Body During Sleep: A Children’s Guide
Sleep is important to your health and well-being. It’s what gives you energy to get through your day. It also helps you to be creative, pay better attention in school, and more easily solve problems. A good night’s rest also gives you the power to fight against sickness so that you stay healthy. Every hour that you’re asleep, your brain, organs, muscles, and nerves are refreshing and preparing for the next day. If you don’t get enough shut-eye, you may feel sleepy and sluggish until you catch some more Z’s.
How Sleep Works
When you’re asleep, your body is in a resting state. You’re usually lying down, your eyes are closed, your muscles are relaxed, and you’re not aware of what’s going on around you. At night, the brain makes a chemical called melatonin that makes you tired. In the morning, sunlight tells your brain it’s time to wake up and start your day. Because light helps to wake you up, even the light from a TV can keep you up at night. Sleep is made up of five stages. It takes about 90 minutes for you to go through all of the stages of sleep, and the entire cycle is usually repeated about five or six times during the night.
Stage 1 is the lightest stage of sleep and happens when you’re drifting off. During this stage, you can be woken up easily. This is also the stage when you may have the feeling that you’re falling. Stage 1 is also the stage in which you wake up if you are not woken by an alarm clock or your parent. This stage is short, lasting just five to 10 minutes. During Stage 1, the eyes move slowly, muscle activity slows down, and your body relaxes to allow you to reach Stage 2.
When you reach Stage 2, your eye movement stops and brain waves slow down. However, there are still short bursts of higher brainwave activity, called K-complexes and sleep spindles. Your breathing and heart rate also slow down, and your body temperature falls a little. There are no dreams in this stage. Its main purpose is to relax and prepare the body for a deeper stage of sleep. You spend about half of your entire night in Stage 2.
In Stage 3, your brain shows delta-wave or slow-wave activity. There may still be short bursts of faster activity throughout this stage, known as beta-waves. During this stage, you cannot be as easily woken up. If you do suddenly wake up, you will probably be confused and groggy. It will also be hard to focus for a couple of minutes. There is no voluntary muscle movement or eye movement, and there is also no dreaming. Stages 3 and 4 are when most sleepwalking occurs. Stage 3 usually lasts about 30 minutes.
Stage 4 is the deepest stage of sleep, making it difficult to wake someone up. This stage shows only delta-wave activity in the brain, and muscle activity is greatly decreased. If you are woken up during Stage 4, you may have trouble thinking clearly. If you’re going through Stage 4 for the first time in a night, you’ll likely remain in this stage for about an hour. This time allows your body to repair itself. Future occurrences of Stage 4 might only last about 5 to 15 minutes.
Stage 5 is also called REM, which stands for rapid eye movement. During REM sleep, the eyes move around quickly. Your blood flow, brain activity, and breathing speed up. The first period of REM usually starts about 90 minutes after you fall asleep and lasts about 10 minutes. Throughout the night, the REM stage becomes longer. The final REM period lasts about an hour. Stage 5 is usually the stage when you dream.
Not Enough Shut-Eye
If you don’t get enough rest at night, you may feel tired or cranky the next day. You may find it hard to concentrate at school and at home. You probably won’t have the energy to have fun with friends or go to sports practice or other activities. When you don’t get enough shut-eye on a regular basis, you may not grow as well as you should. Not enough rest can also affect your immune system, which prevents you from getting sick.
Founder & Editor-in-ChiefDerek Hales is the Founder and Editor-in-Chief of Sleepopolis. Derek has tested over 100 of the most popular online mattresses, and scores of other bedding accessories. His testing approach is grounded in objective criteria and personalized in-depth research. Derek lives in Phoenix, Arizona with his wife Samantha and dog Tibbers.