The power of napping… how a daytime doze can boost memory and beat pain

    5 May 2016

    The secret to a long life? Nap often and nap well. That is the philosophy of Merlin in T.H. White’s Once and Future King, and he lives at least nine centuries. ‘First I think I shall have a little nap before luncheon,’ he tells his owl, Archimedes, ‘and then I think I shall have a little nap before tea. Then I shall have to think of something I can do before dinner. What shall I do before dinner, Archimedes?’ Naturally, Merlin decides on a little nap.

    But is a daily nap (to say nothing of three daily naps) really as wizard a wheeze as Merlin would have us think? Is dozing off over your Spectator after lunch a reliable afternoon pick-me-up of benefit to body and brain? Or does napping disrupt your natural sleep cycle, contributing to insomnia and other sleep disorders?

    There is no tradition of an afternoon rest in this country; nothing like the Spanish siesta. But when you consider that some of the greatest statesmen, philosophers, writers and artists were habitual nappers, perhaps there is an argument for it.

    Winston Churchill was devoted to his afternoon nap, which he called ‘that refreshment of blessed oblivion’. Henri Matisse napped after lunch, Thomas Mann for an hour before tea, and P.G. Wodehouse for an hour after. Kingsley Amis napped after a Macallan malt at the Garrick Club. Architect Frank Lloyd Wright napped on a concrete ledge.

    There are benefits both mental and physical to napping. A study last year at Allegheny College, Pennsylvania, published in the International Study of Behavioural Medicine, found that students who had a catnap of no longer than an hour had significantly lower blood pressure when faced with a complicated mathematical problem than those who had not slept. The study concluded that daytime napping may have a positive effect on cardiovascular health and in coping with mental stresses.

    Another study last year at Saarland University found that napping also helped with memory function. -Participants had to learn lists of 90 single words and 120 unfamiliar word-pairs such as milk-taxi. Half were then allowed a 45–60 minute nap, while the other half watched a DVD. When it came to remembering the words, the nap group accurately remembered five times as many words and word-pairs as the DVD group. The study concluded that a short nap after a concentrated period of learning ‘plays an important role in memory consolidation’.

    Napping may even prove a useful weapon against pain. One study published by the US National Library of Medicine examined the effects of sleep deprivation and sensitivity to pain on 11 healthy male volunteers. They were permitted to sleep only between 2 a.m. and 4 a.m., then subjected to sensory tests measuring their response to intense cold, heat and pressure on three areas of the body: the supraspinatus muscle of the upper back, the lower back and the thigh.

    After sleep deprivation, the men reported greater sensitivity to pain, particularly in the lower back, than after a full night’s sleep. However, when the sleep-deprived night was repeated with two 30-minute daytime naps afterwards, they became much less sensitive to pain. Napping was a natural analgesic.

    So if you aim to embrace ‘blessed oblivion,’ and its potential benefits to blood pressure, memory and resilience to pain, how best to go about it?

    Stephanie Romiszewski, a sleep physiologist and director of the Sleepyhead Clinic in Exeter, says that a nap after lunch — between 2 p.m. and 4 p.m. — is the best way to avoid interfering with night-time sleep because we experience a natural ‘circadian dip’ at this time. A nap, she adds, can ‘recharge your batteries’ if you are sleep-deprived and need to be more alert for activities such as driving. She does, however, caution: ‘If you’re not waking up refreshed in the morning or you find it difficult to initiate or maintain night-time sleep, you can bet that napping during the day is either the cause or it is exacerbating the problem.’

    The nap should be brief, too. A Nasa study of -military pilots and astronauts, whose jobs disrupt their natural sleep cycles, worked out that the ideal length of a nap was 26 minutes. This improved performance (measured by response to stimuli and problem-solving) by 34 per cent and alertness (measured by rapidity of response) by 54 per cent.

    You can make sure you don’t waste the whole afternoon dozing with an alarm clock or stopwatch timer set to go off after 26 minutes, or with a smartphone nap app such as Sleep Cycle Power Nap (£1.49 from iTunes).

    The UK Sleep Research Council recommends a cup of coffee before you lie down. Caffeine, the logic goes, takes around 20 minutes to take effect, so you’ll wake from your nap alert, rather than groggy. But Dr Matthew Hind, a sleep physician at the Royal Brompton Hospital, is sceptical. ‘I wouldn’t recommend having a coffee then trying to sleep,’ he says. Indeed, he has reservations about napping full-stop. ‘We don’t really advise it,’ he says. He treats patients with insomnia and other sleep disorders and warns that though it is tempting to have a nap to get you through the day after a bad night’s sleep, really, ‘It’s the worst thing you can do.’

    It is crucial, he says, to ‘reset your normal routine’. Napping only contributes to a vicious circle of sleepless nights and exhausted days. ‘It’s really only deep sleep that leaves you feeling refreshed,’ he adds.

    He recommends the Sleepio app, developed at the Sleep and Circadian Neuroscience Institute at the University of Oxford, as a useful tool for re-establishing a normal sleep pattern without resorting to naps in the day.

    Needing a nap may also be a sign of an underlying health problem such as sleep apnoea — a contraction of the walls of the nose and throat that blocks the airways. ‘Anyone who snores, or who takes a slightly larger collar, or who gets up to pee, is likely to be sleeping badly and should talk to an expert,’ says Dr Hind. He does, however, concede that there is great pleasure, if you’re not suffering from a debilitating sleep disorder, in the occasional nap on holiday.

    So you may take your siesta on a sun lounger or on a Saturday afternoon without guilt, and awake, like Churchill, with all ‘vital forces’ renewed.