Sleep is a very important relaxation phase of the organism that ensures health and survival. The quality and length of sleep plays an absolutely crucial role in how we feel during the day, how much energy we have and how healthy we are. You should go through 5 REM sleep cycles per night. One sleep cycle lasts 90 minutes. Multiply that by five sleep cycles and you have 7.5 hours of sleep. From this information, it can be concluded that the optimal length of sleep is between 7.5 and 8 hours.

Statistically speaking: The average adult sleeps about 7 hours a night. 33% of the population sleeps 6.5 hours a night. No wonder that people often feel irritated and unfocused. Studies show that people who sleep less than 6 hours on average gain twice as much weight in six years as people who sleep 7 to 8 hours a night. Oversleeping is not the solution either. People who sleep more than 9 hours have a similar weight problem as people who sleep less than 6 hours.