Getting a good night’s sleep is essential to our bodies ability to function. There are many theories on why we need sleep ranging from cellular process to cognition to sleep being the key to the brain’s ability to reorganise (plasticity). Sleep Deprivation also affect the immune system, alters our hormone levels, and increases our risk of diseases.
We require sleep because it restores the brain’s energy and clear out toxic products produced when we are awake. During non-REM sleep, the brain consumes only about half the glucose as it does when a person is awake. The most promising theory of sleep is how it plays a major role in the brain's connectivity and plasticity, which is involved in learning and memory.
Other important functions sleep does is reorganise and communicate with nerve cells and release molecules like hormones and proteins to ensure our body stays in peak health. While we may not be able to explain why we sleep we know that it makes us feel more alert, happier, and energetic. We need sleep due to our internal body clock which regulates our sleep cycle by controlling when we feel tired and require bed or are refreshed and alert.