Depression, wrinkles, less sex: what lack of sleep really does to you
We know we need enough – but what happens when we don’t get it? And what is ‘enough’ anyway? Claire Coleman asked the experts…
We have, it seems, become a society obsessed with sleep – how much we’re getting, how fractured it is, what constitutes enough… And perhaps it’s not surprising. Since the pandemic began, researchers around the world have been documenting a surge in sleep disorders, fuelled by stress, anxiety and lockdowns, that’s been referred to as “coronasomnia” and just last week yet another study revealed the impact of not getting enough sleep. Researchers at the University of Chicago found that going to bed 75 minutes earlier every night helps you consume 270 fewer calories each day. But it’s not just your weight that suffers when you’re sleepdeprived. There’s barely a bodily function that sleep doesn’t have an impact on, which means a lack of it can have devastating consequences.
“Getting enough good-quality sleep is vital for many aspects of mental and physical health and well-being,” explains sleep psychologist Dr Lindsay Browning (troublesleeping.co.uk), author of Navigating Sleeplessness. “Not getting enough sleep is correlated with an increased risk of depression, anxiety, weight gain, diabetes, heart disease, stroke and a number of other conditions.” In fact, sleep is so important that sleep physiologist Dr Guy Meadows, founder of the Sleep School (sleepschool.org) refers to it as “the ultimate pillar of health and the single most powerful performance-enhancing behaviour known to mankind”. Alongside diet and exercise, sleep has a crucial role to play in making us happier, healthier, fitter and smarter, which is why Dr Browning points out that getting up at 5am to go to the gym is basically sacrificing one healthy behaviour for another – unless you’re going to bed earlier as well.
WHY IS SLEEP SO IMPORTANT? “Broadly speaking, sleep is when our brain sorts stuff out,” says Dr Browning. “It gets rid of any unwanted substances, it files and processes new information, it helps produce our immune system and it also helps produce the hormones our body needs.”
These hormones are absolutely crucial to the smooth running of our bodies, as endocrinologist Dr Nicky Keay, clinical lecturer at UCL, chief medical officer of home-blood test company, Forth (forthwithlife.co.uk), and author of the forthcoming book Hormones, Health & Human Potential, explains.
“Hormones control a large number of processes in the body and they are finely tuned to our internal biological clocks, with the levels of hormones released in a timed fashion on a daily, monthly or lifetime basis,” she says. It’s not just that certain hormones are produced when we sleep, it’s that if our sleep is out of sync with what our hormones are doing, we end up with everything out of sync. If you think about how you feel when you’re jetlagged – all of the body’s processes, from cognitive function to digestion, just don’t seem to be working properly. And not getting enough good-quality sleep is like being in a permanent state of jet lag.
WHAT IS “ENOUGH” SLEEP? “How much sleep you need varies from individual to individual and is influenced by a variety of factors, including genetics and age,” says Dr Browning. “The more active you are and the more you’re learning, the more sleep you need, so we tend to need less sleep as we get older.” According to Dr Meadows, the vast majority – 97 per cent of the population – need between six and nine hours of sleep a night.
“There is a very small group of people, known as short sleepers, who can be perfectly healthy on just four hours a day,” says Dr Browning. “But this is very rare and you can’t train yourself to be a short sleeper.
“If you fall asleep in under half an hour, don’t wake during the night for more than half an hour, you’re not waking more than about half an hour before your alarm goes off and you feel refreshed when you wake up, you’re probably getting enough sleep.”
Dr Browning also points out that sleep comes in cycles and that it’s quite normal to wake between cycles, even if you’re not aware of it.
“Roughly every 90 to 110 minutes, you’ll go through a full sleep cycle that includes light sleep, deep sleep and dreaming or REM sleep. Almost all of us wake between these cycles, but if you’re not awake long enough to register that, you’ll assume you’ve had unbroken sleep, but it’s quite normal to wake a few times in the night, and not a sign of poor-quality sleep.”
These sleep cycles can also work to your advantage. If you’re struggling to sleep at night, it’s better to work on that, but if shift work or having a young child mean that’s not possible, the aim is to get the number of sleep cycles you need within a 24-hour period, so that might mean two blocks of four hours, or several naps – ideally of around two hours so you’re getting a full sleep cycle.
But if you’re not getting enough sleep, it shows – in the short term – and if it persists over a period of years, in the long term, too (although experts find it difficult to pin down at exactly what point – a year, two years, more – chronic lack of sleep means you can be at increased risk of a range of conditions).