Experts have been telling us for so long that we need a good seven to eight hours of sleep every night that we’ve almost dozed off. And yet, even when we do manage to get our eight-hour shift, we still feel that we haven’t slept enough.

There are two reasons for that. The first is that sleep is so pleasurable that the more we sleep, the more we enjoy it. And secondly, even though research gives us a ballpoint figure for how much sleep adults require, sleep needs are very individual and depend on our health and lifestyle. Our sleep needs are also influenced by two factors: basal sleep need and sleep debt. While the first is the amount of sleep our bodies need on a regular basis, thesecond is the accumulated sleep that is lost to poor habits, sickness, and environmental factors which keep us awake, such as loud neighbours.

There is strong evidence that disturbed sleep compromises our mental and physical performance

This explains why at times, we get our right amount of basal sleep but still feel tired: that is probably because we still have an amount of sleep debt that we need to sleep off. Not getting enough sleep affects body and mind. There is strong evidence that disturbed sleep compromises our mental and physical performance as well as mood.

Sleep deprivation can also be dangerous since it also affects our alertness while we’re working and driving. On the other hand, research also shows that sleeping too much can be risky and is associated with increased morbidity.

Even though researchers are still learning about sleep, one thing is certain: no matter how much sleep you need, the most important thing is that you sleep well.