Have you been prioritising eight hours a night but still feel tired? Here’s why long sleeps aren’t always restorative.
A good night’s sleep is often defined by its length. We’re told that getting eight hours is the best way to wake up feeling restored and dutifully count the hours to set an optimum alarm. More recently, the importance of sleep quality has hit the mainstream conversation. We now know that we can’t just lie in bed for a long time, but that we need to make the most of the hours we’re tucked up for.
New research by the University of California suggests that there are some ‘elite sleepers’ who can manage both – packing great quality sleep into just a few hours. The study, on people with familial natural short sleep had the ability to function fully on – and have a preference for – four to six hours of sleep a night. They are investigating how to use their genes to help the rest of us get a good night’s sleep. Until then, the question of quality v quantity remains for the majority of us.
“Sleep offers us so much; it gives our body the chance to repair and rejuvenate and our mind the chance to clear out the rubbish and file away events of the day,” says physiologist and sleep expert Dr Nerina Ramlakhan. But when it comes to reaping those benefits, what do we prioritise: quality or quantity?
Why is sleep quality important?
“Deep, velvety, nourishing sleep is the key to feeling refreshed and rejuvenated each day and keeps our energy levels stable,” says Dr Ramlakhan. “This deep sleep is really what will enable our bodies and minds to be totally prepared for the next day. It is not the junk many of us are used to getting, that sleep that is muddied by the noise and stimulation of the day. Rather, it is clear, pure, deep, restorative and rejuvenating,” says Dr Ramlakhan.
Essentially, we can’t feel rested without reaching this deep sleep; a 2009 paper found that disruption of slow-wave stages increases daytime tiredness and reduces our ability to function.
You don’t always have to be out for ages to fall into this kind of a well-rested snooze, though. According to the Sleep Foundation, deep sleep stages can last around 40 minutes at the beginning of the night but reduce the longer you are in bed.
As deep sleep is prioritised earlier in the day, even short naps can make us feel replenished, says Dr Ramlakhan. “Short sleep can be very restorative if done in the right way. I encourage my clients to nap in the afternoon if they are feeling run down, overwhelmed or burnt out. Ideally, it’s a power nap of 10-20 minutes no later than 4pm,” she says.
Why sleep quantity matters
Requirements can vary from person to person, but most adults will need around seven or eight hours. Yet, studies suggest most of us only get a measly six and a half. “There are times when we can get by on less and times when we need more, but getting the right number of hours is an important consideration,” says Dr Ramlakhan.
Research published in the Sports Medicine journal shows that a ‘sleep extension’ – getting more of it – improves athletic performance. And, in the world’s largest sleep study of 400,000 people in 2018, researchers found that those who slept for four hours or less had the brain cognition of someone who was nine years older. Researchers also found that too much sleep has downfalls too, including impairments in overall cognition, reasoning and verbal abilities. “Oversleeping can cause inertia and lethargy, so avoid lying in bed for too long,” says Dr Ramlakhan. It seems quantity really does matter too.
How to get the best sleep
Quantity and quality go hand in hand, says Dr Ramlakhan. That’s because the longer you sleep, the more cycles you will go through and the longer you’ll spend in the deep, restorative stages.
A 2011 study found that reduced sleep efficiency was associated both with short sleep and spending a long time in bed – meaning it was impossible for researchers to distinguish whether quantity or quality is more important.
But perhaps more important than total length is the timing of when we get to bed. Sleeping for eight hours between 1am and 9pm isn’t going to be as restorative as an earlier sleep-wake schedule. Pre-10pm bedtimes have been shown to come with a number of benefits, but it also means we are giving our bodies the chance to get more time in the restorative zones.
“The key to great sleep is to get to it earlier (between 9:30-10pm) and rise at a similar time each day – between 6.30-7am is a good time for most people,” says Dr Ramlakhan. “You also need to value yourself enough during the day to make healthy choices, including eating breakfast, exercising and exposing yourself to natural light. This will help you achieve that deep nourishing sleep we all need.”
Chloe Gray is the senior writer for stylist.co.uk's fitness brand Strong Women. When she's not writing or lifting weights, she's most likely found practicing handstands, sipping a gin and tonic or eating peanut butter straight out of the jar (not all at the same time).