Later – not worse?
With the onset of twilight, at about 20-22 hours, melatonin, the so–called sleep hormone, begins to be released into the blood. It was called so for a reason: there was an opinion that the desire to sleep appears just when the level of this hormone begins to rise. Therefore, the time from 20 to 22 hours was considered suitable for going to bed. Recent studies have refuted such conclusions. After studying the schedule of falling asleep and waking up of primitive tribes of South America and Africa, scientists noticed that representatives of these tribes go to bed not when melatonin levels begin to rise, but about 1.5 hours later. Falling asleep is associated with a decrease in body temperature. Something similar happens around 22 hours.
According to modern recommendations, it is not the time of going to bed that is important, but its duration. Yes, it is advisable to fall asleep when natural and artificial lighting, as well as body temperature are minimal. The minimum values of body temperature are at 5 o’clock in the morning, then it begins to rise. Therefore, theoretically, it would be ideal to fall asleep at 22 o’clock and wake up in the morning at 5-6 o’clock. But, as practice shows, the real time of laying and lifting from these conditional standards can be very different and nothing terrible happens with «violators». The main thing is to get enough sleep.
For adults, the optimal sleep duration is 7-9 hours. If young parents go to bed at one in the morning and wake up at 8-9 in the morning, they get their sleep rate.
If we take into account the production of the stress hormone cortisol, the recommendations change slightly. Its level begins to rise after 2 a.m. and reaches a peak in the morning. If you go to bed at this time, it may be difficult to fall asleep. Whether the quality of sleep will suffer from this – opinions on this matter vary, but none of them has been scientifically proven.
Sleeping longer makes it easier to lose weight
A special part of the brain, the hypothalamus, is responsible for the mechanisms of sleep and wakefulness. It also regulates body temperature and metabolic processes in the body. During sleep, inhibitory systems are activated in the hypothalamus, which suppress the production of hormones of «vivacity» – cortisol, norepinephrine, acetylcholine, histamine and others. When a person sleeps, breathing, heartbeat, digestion slow down. It is not necessary to mock him, reducing the rest time of his main systems. In addition, the theory is now popular that during sleep, the brain receives almost no signals from the outside. Due to this, priority is given to signals from internal organs – intestines, liver and others. The brain actively processes them. It is assumed that this is what helps the internal organs to restore their functions. If we follow this theory, then by reducing the duration of sleep, we do not allow the body to fully recover.
And, finally, a very important circumstance for young mothers who dream of losing weight after childbirth. Reducing the duration of sleep affects the metabolic rate in the body and contributes to an increase in hunger, which means that it increases the risk of overeating. Hormones are to blame for this again. Leptin is responsible for the feeling of satiety, ghrelin is responsible for hunger. In those who sleep less than 8 hours, the level of leptin decreases, and ghrelin, on the contrary, increases. Therefore, a person begins to experience a constant feeling of hunger. No matter how much willpower you call for help, the fight against it is useless, because hormonal changes are to blame.
Scientific confirmation
The Americans conducted an interesting study. A thousand healthy volunteers were divided into 2 groups. In one, people slept for 5, in the other – for 8 hours. In those who did not get enough sleep, compared with those who slept for 8 hours, the amount of leptin in the body decreased. Even earlier, something similar was noted in experimental mice.
