Sleep is necessary because it allows our bodies to eliminate waste products that accumulate during daytime activities and excrete them with urine. In addition, sleep allows the development of new connections between nerve cells in order to improve memory and cognitive function. In addition, sleep restores the hormone pool and energy reserves depleted by daytime activities.
How many hours of sleep do we need?
Humans need between six and eight hours of sleep per night. People who become centenarians, showing that their health is better than average, sleep a little more than seven hours.
In a study published in 1899, researchers determined that the average sleep time of 52 centenarians was eight hours, and most reported excellent sleep. In the famous French study of 368 centenarians, 80 percent of the centenarians had a restful sleep, as reported by their family members. In a more recent and better controlled study, centenarians had an average of seven and a quarter hours of sleep. A little more than seven hours of good quality sleep seems to be necessary for health and long life.
