We always hear how lack of sleep will leave you a ragged shadow of your former self, wear you down physically and mentally, and even make you fat. But sleeping in has generally been thought to have no other ill effects than making you late for work. Well, scientist have now discovered yet another thing that's bad for you. Sleeping too much can even be fatal, according to a multi decade study.
Researchers at the University of Warwick and University College in London have mapped out the sleeping patterns of a staggering 10,000 British civil servants over a period of more than a quarter century, and compared the amount of sleep they were getting to heakth and mortality rates. And the results will probably surprise quite a few.
After having factored out influences such as age, sex, physical activity level and smoking, the researchers came to the conclusion that not only will too little sleep have adverse effects on your health, but too much as well. They do however stress the point that just how much sleep is optimal varies among individuals.
"Sleep is a bit like height and shoe size. No two people are quite alike. But this study shows how important it is to follow the natural biological rhythm of the body," says sleep disorder expert Neil Stanley at Norfolk and Norwich University.
For most of us that means about seven hours per day. Substantially less, and more than that can have serious effects on your health. Those who force themselves out of bed after only five hours of sleep are twice as likely to develop life threatening heart ailments than those who sleep the full seven.
The study also shows a clear link between lack of sleep and high blood pressure, type 2 diabetes, and dangerous obesity. On average the subjects who got too little sleep had a 1.7 times higher mortality rate.
But the fact that those who slept considerably more also had a statistically higher mortality rate came as something of a surprise. And the researchers are still at a loss to explain just why the health of these people are adversely affected. "But it might be that abnormal amounts of sleep are tied to conditions such as depression, and physical exhaustion due to an illness already present, such as cancer," said professor Francesco Cappuccio at the University of Warwick.