What happens to the body when one doesn't get enough sleep?

Sleep deprivation causes fatigue, low energy and excessive sleepiness, which can affect one's ability to complete day-to-day tasks. It can cause stumbling, and can be a symptom of mental health issues. Lack of sleep also affects one's ability to remember and react. Sleep deprivation can also cause neurological disturbances like blurred vision, memory lapse and poor reaction time.