Between the caffeine and blue-light screens, it seems like everything we come into contact with is designed to keep us stimulated, awake and productive. And the pandemic has inevitably impacted sleep too. With no early morning commute or school drop-off to worry about, many were sleeping later for longer. Matthew Walker – professor of neuroscience and psychology at the University Of California, Berkeley, and author of Why We Sleep – calls this the “revenge of the night owls”. However, lockdown has been a time of increased anxiety and stress for many others. Nearly 70 per cent of respondents to a 2020 British Sleep Society survey reported that the pandemic had impacted their sleep pattern, with less than half saying they were satisfied with their current sleep quality or felt refreshed from sleep.
A good night’s kip is essential for maintaining our overall wellbeing – it supports growth and development and promotes healthy brain function – and getting too little leaves you vulnerable to both physical and mental health problems. So we’ve asked some well-rested experts all the big questions about sleep: how much, when and why…
Eight hours a night, right?
Not quite. The “optimal” amount varies from person to person, but studies around the world suggest that the vast majority of adults need between seven and nine hours sleep per night.
The type of sleep we’re getting is important too. Sleep occurs in cycles of 90 minutes, during which we encounter light sleep, deep sleep and the REM stage, each of which is essential to our overall health and wellbeing. “Historically, we’ve thought of non-REM sleep as being the stage of sleep that’s important for restoration of function, for recovery, for regulation of immune function and growth,” says Guy Leschziner, professor of neurology and sleep medicine at King’s College London and author of two books on sleep (The Nocturnal Brain and The Secret World Of Sleep). “It’s thought that REM sleep is perhaps more important in certain aspects of learning and of regulation of emotion. It’s likely that, actually, it is the balance of non-REM and REM sleep that is important for many of these functions.”
What determines how much sleep I need?
Age affects how much sleep we need – teenagers, for example, will generally need more hours – but it remains pretty much stable once we reach adulthood.
“There are a very rare few genetic mutants out there who have a short sleeping gene, who can perhaps survive on maybe six hours and 15 minutes,” says Walker. “To give you some statistical context, it’s much more likely that you will be struck by lightning in your lifetime than be one of these individuals.”
Similarly, very few people require more than nine hours sleep. “You have to be someone who is doing things in extremes before you extend beyond the bounds of what is normal for most people,” Walker continues. “A good demonstration would be elite athletes. Because of their physical training, they may need a higher sleep amount.” Basically, unless you’re Usain Bolt, seven to nine hours should suit you just fine.
Should I be going to sleep at a certain time?
What time you go to bed will ultimately be decided by what time you need to get up, but aligning with your body’s natural rhythm will boost the quality of your sleep. Each of us follows an internal 24-hour clock, known as the circadian rhythm, which tells us when to sleep and when to wake up. This is influenced by many factors – light and temperature among them – but your chronotype also plays a role. Your chronotype is your body’s natural inclination to sleep and wake at a certain time and determines whether you are a morning lark, night owl or somewhere in between. “If you sleep in sync with your internal body clock, the quality of your sleep will be better,” says Leschziner. “Living out of sync with your body clock, even if you are getting sufficient sleep, can have negative effects.”
OK, so how do I figure out what’s right for me?
Figuring out how much sleep you need within the recommended seven to nine hour bounds is pretty much an exercise in common sense. If you wake up feeling refreshed and ready to go, then you’re probably on the right track. Beyond this, there are a few things you can do. “Firstly, if you currently use an alarm and your alarm didn’t go off tomorrow morning, would you sleep past that alarm?” asks Walker. “If the answer is yes, then it means that your brain is not yet done with the sleep that it needs. It still needs more.”
Dr Alanna Hare, a consultant in sleep and ventilation at Royal Brompton Hospital, also suggests establishing a routine and sticking to it. “If you are going to bed and getting up at a different time every night and getting variable amounts of sleep each night, it is impossible to know how much sleep you need,” she says. Pick a waking up time and work backwards from there to establish a fixed bedtime. As above, this should be seven to nine hours earlier. Stick to this routine for two weeks. If you feel exhausted, gradually go to bed earlier. Likewise, if you find you’re unable to fall asleep within 30 minutes, gradually go to bed later. “Keep doing this until you find you are generally waking refreshed and able to comfortably get through your day. That is the amount of sleep you need!”
