How important is it to sleep in at the weekend?
Many people have problems getting enough sleep regularly throughout the week. Those affected then often try to make up for lost sleep at the weekend. Researchers have now investigated how life expectancy affects when people sleep only a few hours a night, seven days a week. The experts also wanted to find out whether the negative effects of little sleep during the week can be offset by sleeping longer at the weekend.
In their current study, scientists from Stockholm University and the Karolinska Institute found that insufficient sleep seven days a week leads to a greatly increased risk of premature death. The doctors published the results of their study in the English-language journal "Journal of Sleep".
Sleep duration is important for longevity
If adults under the age of 65 years sleep only five or fewer hours seven days a week, the risk of premature death increases massively, compared to regularly sleeping six or seven hours, the scientists report. However, the negative impact on life expectancy can be compensated for if those affected generally sleep longer at the weekend. Sleep duration is important for longevity, said study author Torbjörn Åkerstedt from Stockholm University
Data from more than 38,000 participants were analyzed
The current study is based on data from more than 38,000 adult subjects. The data used was collected in 1997 during a major medical investigation. The fate of these participants was monitored for a further 13 years. The scientists used the national death register for this.
Weekend sleep has rarely been considered
Researchers have previously examined the relationship between sleep duration and mortality, but focused on sleep during the working week, explains Åkerstedt. The results would probably change if sleep at the weekend were also taken into account, the expert added.
What was the risk of premature death?
Taking factors such as gender, body mass index, smoking, physical activity and shift work into account, the results showed that participants under the age of 65 who received five hours or less of sleep seven days a week had a 65 percent higher mortality rate compared to six or seven hours of sleeping people every day. However, the risk was not increased if people only slept five hours a night in the week, but slept eight or more hours on weekends.
Too much sleep isn't good either
However, it was also found that people who slept eight or more hours seven days a week had a 25 percent higher mortality rate than those who slept six or seven hours a day.
People over the age of 65 were not affected
The study also observed that the link between sleep patterns and mortality was no longer observed in people aged 65 years and over. This could be due to the fact that these older people no longer seem to need as much sleep, the scientists speculate. The study did not examine the relationship between sleep patterns and mortality rates. However, it is possible that little sleep has a negative effect on the human body, while sleeping too long could be a sign of underlying health problems, the experts explain.
Sleep needs depend on genetics
Too little or too much sleep can appear to be bad for health and longevity. This finding is in line with previous knowledge about sleep, the researchers say. Sleep is regulated by a body's own clock and a so-called homeostatic process. This means the longer you are awake, the more you have to sleep. However, sleep needs seem to vary genetically from person to person. (as)