Study in 21 countries shows: sleep long or short – what is really healthier?

Tough managers boast that they only sleep four to five hours and are still able to make important decisions. Napoleon also called late risers “idiots”. Literally he is said to have said: “Man sleeps four hours, woman five, idiot six.”

Sleep researchers vehemently disagree with these statements. After just one night with less than six hours of sleep, you do worse on concentration tests.

But there are also famous late risers. The brilliant physicist Albert Einstein is said to have slept ten to twelve hours a night.

Why are we sleeping?

The main reason for our need for sleep is our brain. It works at full speed during the day. Sensory impressions and complex information must be processed continuously.

After about 16 hours the capacity of the brain is exhausted. It needs sleep so that the nerve cells can recover. Memory processes take place during sleep, are temporarily stored and are only reactivated when information and impressions dry up. Organs and the immune system can regenerate during sleep, and the process of wound healing also takes place primarily during sleep. At the same time, the body is given the opportunity to detoxify. This means that metabolic products that the body does not need are mainly excreted at night.

The need for sleep changes with age

The need for sleep changes over the course of life.

• Newborn babies start with about 15 hours of sleep, some as many as 20.
• As we get older, our need for sleep decreases. For 20-year-olds, the average is usually around the well-known seven to eight hours.
• By the time people reach retirement age, their need for sleep will decrease by another one to two hours. As we get older, we need even less sleep. But everyone’s sleep cycle is different.

Sleep long or short – it really is better

In a mammoth research project, researchers from Canada asked 117,000 participants from 21 countries what time they go to bed and what time they wake up.

They should also indicate whether and how long they take naps. From this, the researchers calculated the nightly and total sleep duration.

At the start of the study, the participants were on average 50 years old. Around 43 percent slept a total of six to eight hours a day, 26 percent eight to nine hours, and 9.5 percent six or fewer hours. Nine to ten hours required 14 percent and even more sleep 7.5 percent.

Too much or too little sleep is so dangerous

The extreme sleepers in the test were on average a little older, physically sluggish, more depressed, smoked more often and drank significantly more alcohol than the other participants. They also suffered more from high blood pressure and COPD, chronic obstructive pulmonary disease.

Over the course of almost eight years, the researchers observed over 7,300 cardiovascular events in extremely late sleepers. 4,400 participants died, and almost as many suffered a heart attack or stroke.

Short sleepers produced more accidents, indicating that they were not fully rested. Also, the rate of cardiovascular events and deaths appeared to be slightly higher.

What is certain is that too little sleep makes you fat. The reason: There is an imbalance in the hormonal balance. With too little sleep, the body no longer produces enough of the hormone leptin, which curbs our hunger. In return, more ghrelin, an appetite-stimulating peptide, enters the stomach.

This substance makes you eat more. This seems to be confirmed by the study with its increased proportion of overweight and diabetic people among short-sleepers.

How much sleep is healthy now?

The researchers found the fewest negative events in the group with six to eight hours of sleep. The results show that too little sleep is not healthy, while late sleepers tend to be unhealthy. There may be an underlying condition behind an unusual amount of sleep.