Why a regular bedtime is more important than how many hours you sleep

Regular sleeping hours are the key for optimising your circadian rhythms
Regular sleeping hours are the key for optimising your circadian rhythms - iStockphoto/Uzhursky/iStockphoto

It often feels as though good health has become a numbers game. Need to move more? Just get your 10,000 steps. Want to lose weight? Eat within an eight-hour window. Seeking better gut health? No less than 30 daily plants stand between you and a diverse microbiome. Many of us spend our days trying in vain to hit each of those targets. But the hardest one to achieve is surely that elusive eight hours of sleep.

There is some good news on that front this week. Research has found it is the regularity of our sleep patterns that really matters, not the number of hours we are clocking up. A new study looking at sleep and longevity concluded it would be better to sleep for six hours every night, consistently falling asleep and waking up around the same time, than to vary the number of hours we sleep.

The study, published in The Journal of Sleep, found that regularity of sleep reduced the risk of premature death by 20 per cent when compared with those with the most irregular sleep patterns. Duration was still deemed important (clearly, if you get three hours a night, you’re still not getting enough, even if they’re the same three hours) but shorter, more regular sleep was associated with lower mortality than longer, inconsistent sleep.

We like routine

It’s partly because the body likes routine, says Guy Leschziner, a professor of neurology and sleep medicine and author of The Nocturnal Brain. “All our biological rhythms run on a 24-hour cycle,” he says. “We have areas of the brain that are highly specialised for regulating that circadian clock, and all our other organs have that circadian clock as well.” Those biological rhythms are “optimised”, he says, when they are “consistent”. Sleeping “counter to one’s circadian rhythm” can be hugely detrimental to our wider health, he adds. “[It] may even be a risk factor for cancer. The World Health Organisation a few years ago added shift-work disorder to one of its possible carcinogens.”

Fostering more consistency around sleep isn’t just a helpful way to maintain that all-important circadian rhythm, he says – it can actually improve the quality of your sleep too. “Sleep is a learned habit,” says Prof Leschziner. “What you’re trying to do – and this is often the difference between good quality sleep and bad quality sleep – is to establish a particular pattern of behaviour with your environment.” Going to sleep at the same time every night, then, and setting your alarm for the same time every morning, will help “strengthen the subconscious associations between bed and sleep and make it more likely for you to have a good quality of sleep”.

Lie-ins don’t do us any good

It’s bad news for that weekly Sunday lie-in you had hoped was making up for days of restless nights and early alarms. Regular lie-ins aren’t as effective for “catching up” as you think. Prof Leschziner warns that Sunday morning sleep may not be doing quite as much heavy lifting as you’d hoped. “Regularity trumps catch-up,” he says. “If you catch up at the weekend you might be less sleepy but the cognitive effect of sleep deprivation may not be fully reversed.”

Even if you sleep until 11am on Saturday and Sunday, it may not be enough to make up for poor sleep in the week – in fact, those peaks and troughs could be detrimental. “You may not be fully repaying your sleep debt. If you have a significant lie-in, for example on a Sunday morning, then what you may be doing is making it more difficult for you to drop off to sleep in a timely manner on Sunday night. You may actually reduce the quality of your sleep on Sunday night.”

It’s a bit like the old-fashioned rule about eating five types of fruit and veg a day, says Dr Lindsay Browning, a sleep expert and author of Navigating Sleeplessness. “You can’t just eat rubbish during the week and then at the weekends have salads.” Similarly, two days of 10-hour snoozes won’t make up for five days of deficit.

Addressing your sleep hygiene can help inject some more regularity into your sleep. There are things you can do to “biohack” your circadian rhythm, says Dr Browning. As a general rule of thumb, she says, the more regularity there is in other areas of your life, the easier it will be to iron out your sleep. You need to think about your movement, your eating patterns, your exposure to sunlight. And crucially, you need to try to introduce some routine into all three.

The importance of sunshine

If you find it hard to go to bed early and wake up when you need to, says Dr Browning, you may need to “pivot” your circadian rhythm by exposing yourself to more sunshine in the mornings.

“If you are finding that it takes you a lot of time to fall asleep, but once you are asleep you could sleep in late, then it’s almost as if you were jet lagged and your time zone was a bit too forward – your body thinks bedtime is 1am and morning 10am. “In those cases, getting bright sunshine as soon as you wake up is really important, because that will help to pull your body earlier.” Conversely, if you find yourself falling asleep in front of the TV at eight and waking up at four, you may want to try getting out for a walk later in the day while it’s still light.

Consider your eating patterns too, particularly at the beginning and end of the day. “Eating breakfast and dinner at a fairly regular time helps to give those signals to your body – we’re awake now and asleep later,” says Dr Browning Don’t eat dinner too close to bedtime. “You’re telling your body: ‘hey we’re still awake’. Even if you went to sleep your body wouldn’t be giving you the same benefits of that [early] part of sleep because it thinks you’re still awake.”

The biggest hack? Not allowing yourself to hit that snooze button. “I am absolutely passionate about the fact that no one should ever use the snooze button,” she says. It sounds counter-intuitive – surely an extra 20 minutes can only do you good? Not so. “It wrecks your sleep quality. It’s much better to give yourself that extra half hour.”

Cast off the shackles of the eight-hour sleep goal, then. It’s time to usher in a new phase of sleep regularity. Your longevity could depend on it.


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