One berates his alarm clock, the other jumps out of bed cheerfully even after a short night. But almost everyone notices: your night’s sleep becomes more and more precious from a certain age. A British study, conducted on more than half a million people over the age of 38, sheds light on exactly how much sleep you need. And, too bad for late sleepers, unfortunately, you can also spend too long in dreamland.
A lot of ink has been spilled about our sleeping habits. Logical too, if you know that more and more people suffer from insomnia. Some articles explained that we now focus too much on the quantity of sleep, and should take more care of its quality. And yet one of the most frequently asked questions remains: exactly how many hours of sleep do you need to get through the day fit and cheerful?
A recent large-scale UK study sheds new light on the issue. The study, which involved nearly half a million adults between the ages of 38 and 73, found that seven hours is the ideal amount of sleep for middle-aged and elderly people. So lucky, number seven! The less that number fluctuated, the better.
Striking: not only if you sleep less, but also if you sleep longer than the acclaimed seven hours, it appears to have consequences for your health. “For every hour you were away from those seven hours, your physical and mental health deteriorated,” said Professor Barbara Sahakian of the University of Cambridge’s Department of Psychiatry. “That makes it clear how important the processes that take place in our brains during our sleep are.”
A smaller brain volume
Those who had slept too little or too much had a worse cognitive performance. In addition, their mental health fluctuated, and they were more likely to suffer from anxiety or depression. The area of your brain most affected by your sleep turns out to be the hippocampus or the brain’s memory center. If you slept too much or too little, this resulted in a smaller brain volume.
The people with seven hours of sleep on the counter, on the other hand, scored the best on all tests: they processed information faster, were visually more attentive, their memory failed them less, and their problem-solving ability was significantly better.
More hours, less quality
The fact that more than seven hours of sleep turns out to be harmful to your health also caused the researchers themselves to frown. “We don’t really understand why longer would be a problem,” admitted Professor Sahakian. One potential explanation could be that people who spend so many hours in bed have poor quality sleep. They sleep longer in the hope that they will finally get rid of that tired feeling.
Is it really bad if you get more or less than seven hours a night? Psychologist and sleep coach Annelies Smolders reassures: these are averages. “The number of hours of sleep you need varies from person to person. Some people need more sleep than others. So it makes no sense to stare blindly at those seven hours. If you have shoe size 40, you are not going to squeeze yourself into a size 36, are you?”, she previously explained. “Note, sleeping less than six hours each night is harmful to your health.”
Focusing too much on those seven hours a night can actually work against you. Imagine: after six hours under the sheets you are suddenly wide awake. Then there is no point in staying still. Or what if your alarm clock indicates that you can only sleep for six hours? Then there’s a good chance that you start to worry because you don’t get enough sleep, et voilà, you toss and turn for the rest of the night. The only solution: try as much as possible to get under the wool at the same time and find your own sleep rhythm.