Is an hour’s sleep before midnight as good as two after? Can a lie-in at the weekend make up for late nights during the week? We separate the fact from the fiction

Is a power nap or siesta a good idea if you’re exhausted?

A siesta is not the same thing as a power nap. Siestas are a cultural norm in certain places (particularly in hot countries) where people take a brief rest after lunch. We can do this because our circadian biology (body clock) has a natural dip in the afternoon and there is a natural lull in our alertness. If we are extremely sleepy during the day then we should stop and take a nap – especially if our jobs require alertness (lorry drivers, for example). A nap of 15-25 minutes avoids getting into deep sleep, but can still renew levels of alertness and restore the brain’s capacity for learning – and even improve mood. However, sleep is not a commodity to be turned off and on as we see fit. Naps don’t replace the need for night-time sleep.

Is an hour’s sleep before midnight really as good as two after?

No, but everyone should make sure they get enough sleep. Don’t burn the candle at either end.

Can we catch up on lost sleep during the week with a lie-in at the weekend?

To some extent, but it’s important to remember our daytime performance during the week will be suboptimal when we have had insufficient sleep during night-time. Sleep is a better investment in productivity overall than working too late and depriving ourselves of sleep.

If I wake up during the night, have I got a sleep disorder?

Not necessarily. Everyone has arousals at night, but if they are frequent and troublesome then you should make an appointment with your GP.

Does counting sheep get you to sleep?

Not according to research conducted by Oxford University in 2002. It’s “just too mundane to effectively keep worries away”, according to cognitive psychologist Dr Allison Harvey. In test groups, those who thought of idyllic, beautiful places, such as a beach in the south of France, went to sleep on average 20 minutes earlier than they would normally do on nights when they were not concentrating on faraway places. The sheep counters actually stayed awake for longer than their normal ration of restlessness.