Too much sleep
We’ve all heard many times that getting a good night’s sleep is the key to staying healthy. Persuading young children to go to bed early is never easy, and teenagers are often reluctant to get out of bed in the mornings. However, it seems that getting too much sleep could actually be bad for us. Researchers have discovered that sleeping between seven and eight hours per night is the optimal sleep duration, which means if you sleep for this amount of time, you are least likely to become ill.
The research was carried out in Finland on people aged between 30 and 64. The purpose was to try and find a link between sleep duration and absence from work due to illness. So, maybe some of us ought to stay up a bit later or get up a bit earlier.
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optimal the best, the most useful
ought to should