What are the effects of long sleep

Too much sleep is also unhealthy

Warwick / Tempe / Worcester - Fatigue, poor concentration and a higher risk of cardiovascular diseases: If you sleep too little, you damage your health. But too much bed rest could have negative consequences, researchers now suspect. The magical eight-hour rule for a good day after a good night's sleep could fall with it.

Franco Cappuccio, professor of cardiovascular medicine and epidemiology at the University of Warwick, analyzed the data of more than a million people who had recorded their sleep patterns and well-being in writing over an extended period of time. To this end, he first divided them into three groups: the group of short sleepers who sleep less than six hours; the group of late risers with more than eight hours of sleep per night; and the group in between, who rest between six and eight hours a day.

Higher mortality among late risers

The results were clearly negative for the marginalized groups: The number of deaths among short sleepers exceeded that of the middle group by twelve percent. The late risers fared even worse: their mortality rate was 30 percent higher than the rate of the average group. Long sleep is reflected in the mortality rate in a similar way to regular increased alcohol consumption.

Is too much sleep actually more unhealthy than too little? Cappuccio suspects that the length of sleep is not the cause, but a symptom of the real problem. An as yet undiscovered physical or mental illness sometimes manifests itself in an increased need for rest. For example, the subjects in the study could have suffered from depression.

Lying down for science

Other researchers attribute a negative effect to excessive sleep itself. Shawn Youngstedt from Arizona State University researched the medical risks for late risers in an initial preliminary study. 14 young adults spent three weeks in bed two hours longer than usual. He then asked them about the changes: Depressive moods, more frequent inflammations, pain and tension in the back plagued the test subjects.

Representative studies on the negative effects of getting a good night's sleep are still lacking. Even broad-based research such as that by Franco Cappuccio is faced with a problem: people rarely know how long and how well they have really slept. In fact, respondents tend to overestimate the length and quality of their rest periods.

Seven hours instead of eight

However, one thing emerges in sleep research: the number that scientists keep coming across is not eight: the median of the duration of sleep is around seven hours worldwide, says sleep researcher Gregg Jacobs from the Sleep Disorders Center at the University of Massachusetts Medical School BBC interview. He suspects this is a natural constant that, on average, provides the right amount of recovery.

Get up or turn around again? This question will continue to occupy medical research. It remains to be seen whether the average of seven hours of sleep a day is the optimum. (red, derStandard.at, March 26, 2015)