Numerous brain processes, particularly the communication between nerve cells (neurons), depend on sleep. In actuality, when you sleep, your body and brain continue to function amazingly. According to recent research, sleep has a cleaning function that clears your brain of toxins that accumulate while you are awake.

Why is getting enough sleep important? 
The Functions of Sleep and Its Importance | NHLBI, NIH 
Your body supports normal brain function and preserves physical health while you sleep. Sleep is also important for promoting growth and development in kids and teenagers. Over time, getting insufficient sleep can increase your chance of developing chronic (long-term) health issues.

One-third to one-quarter of the human lifespan is spent sleeping. However, what precisely occurs during sleep? 
sleeping-man-istock_000062504918.jpg /sebin/d/v 
Prior to the 1950s, the majority of people thought that sleep was a passive activity in which the brain and body were at rest. Mark Wu, M.D., Ph.D., a neurologist and sleep specialist at Johns Hopkins, says, "But it turns out that sleep is a period during which the brain is engaged in a number of activities necessary to life—which are closely linked to quality of life." Many of Wu's waking hours are devoted to researching these processes and their effects on both physical and mental health. Here is a peek into some of the compelling—and frequently unexpected—research on sleep.

Why Is Sleep So Important? 
Staff of Psychology Today reviewed 
After a long day, sleep is the salve that calms and revitalizes. The body's internal clock, which is influenced by environmental factors like temperature and sunlight, is primarily responsible for regulating sleep. The natural sleep-wake cycle of the organism is roughly synchronized with a 24-hour period. 
Sleep cycle disruptions impair the efficiency of numerous bodily processes. Sleep duration and quality have an impact on mood, general health, memory, learning, and stamina. Many people have problems falling asleep or staying asleep at all. In actuality, most people struggle to fall or stay asleep at some point in their life. Diabetes, heart disease, and obesity are possible outcomes of persistently inadequate sleep.

How long should I sleep for? 
Age-related differences in sleep requirements also occur within age groups. However, The National Sleep Foundation offers the following general recommendations for daily sleep: 
Young children (4–11 months): 12–15 hours 
Children at school (6–13): 9–11 hours 
Teens (ages 14 to 17): 8 to 10 hours 
18 to 25-year-olds: 7-9 hours 
People aged 26 to 64: 7-9 hours 
65 years of age and older: 7-8 hours 
For additional information on how sleep requirements vary with age, see Children and Sleep.