Doctors recommend that adults get enough sleep for 7 hours a day. How much harm does not getting enough sleep do to the body?

Sleep is one of the most basic and important physiological needs of human beings, and 1/3 of human life is spent in sleep. However, according to authoritative surveys by WHO and other institutions, in recent years, the group with sleep problems is showing an expanding trend. Among the many causes of sleep problems, an unreasonable amount of sleep may be an important but easily overlooked one.

When it comes to the best sleep time per day, I believe that the first time you think of is 8 hours. But 8 hours of sleep isn’t always the “best” performance: Sometimes you get 8 hours of sleep and you still feel drained and your brain is lethargic; sometimes you only get five or six hours of sleep and you’re still full of energy throughout the day. Does this prove that 8 hours is not actually the “optimal” length of sleep?

Studies have found that the crude 8-hour sleep theory is indeed unreasonable and may not work for everyone. There is no one “best sleep time” for everyone. It has been proven that the amount of sleep everyone needs is different, some people may need more than 10 hours of sleep, while others only 4 to 5 hours is enough. Planning your own sleep according to 8 hours will only make more people uncomfortable.

In addition, to measure sleep quality from the time level, you should look at how many sleep cycles you have slept in, rather than whether you have enough sleep for 8 hours. Studies have shown that a sleep cycle is 90 minutes. During these 90 minutes, the human body will sequentially go through several stages of non-eye movement sleep, eye movement sleep, rapid eye movement sleep, and enter deeper and deeper sleep. After a cycle of sleep, we wake up and move on to the next sleep cycle, although usually we don’t remember that we ever woke up. So 90 minutes is the basic unit in which we calculate sleep time. Don’t worry about how long and how long to sleep, but to see how many sleep cycles we sleep, sufficient repair and sleep, all go according to the cycle.

Ideally, adults should get 5 sleep cycles per day, or 7.5 hours, and 35 full sleep cycles per week. But actually 28 to 30 cycles a week is ideal. At the same time, the occasional night of poor sleep doesn’t have much impact, as long as you don’t lack sleep cycles for 3 consecutive nights, and get enough sleep cycles at least 4 days a week. Finally, in the arrangement of sleep time, it should be in line with the circadian rhythm of “work at sunrise and rest at sunset”. Sleeping during the day and sleeping at night have completely different effects on the recovery of the body and mind. The sleep lost at night cannot be made up for no amount of rest during the day.