Have you ever wondered why some people leap out of bed first thing in the morning, instantly ready to tackle the day ahead, while others only start feeling productive late in the day? If so, you might be interested to know that much of the variance is controlled by genes – or, to be precise, a protein-coding gene called period circadian regulator 3 (PER3). This helps to regulate our body clocks, controlling the sleep/wake cycle or circadian rhythm.
Mutations in PER3 have led to the existence of “extreme larks” and “extreme owls”. These make up 27% and 9% of the population respectively, according to a 2018 study of 433,268 people published by Kristen Knutson and Malcolm von Schantz in The Journal of Biological and Medical Rhythm Research. Most people, who sit somewhere along a continuum between these two chronotype groups, are known as “hummingbirds”.
Evolutionary psychologists posit that the emergence of larks and owls started as a tribal protection mechanism. Night was the most dangerous time for early humans. It made sense to have people who were able to stay alert, maintain the fire and keep watch overnight. They could then be relieved at dawn by the early risers.
An individual’s chronotype can fluctuate with age. While young children and the over-60s would generally be described as larks, teenagers tend towards owlish before stabilising into their adult chronotype in their mid-20s.
PER3’s influence doesn’t fully account for how our body clocks are set. The suprachiasmatic nucleus – located close to the optic nerve in the hypothalamus region of the brain – also plays a role in regulating circadian rhythms by responding to light and darkness. This means that our circadian rhythms are affected by the varying lengths of day and night over the year too.
A third influence is our own habits. Dr Guy Meadows, clinical director and managing partner at London-based clinic Sleep School, explains: “Beyond genetics, our everyday behaviour also has a strong impact on our sleep/wake timing, especially now, when people are working for longer and later, while exposing themselves to a lot of light-based stimulation from electronic devices for longer and later too.”
The problems of being a night owl
While the times at which we’re at our most effective are partly genetically dictated, there is little acknowledgment for this factor in a civilisation that tends to be organised around early rising.
“Variations on the phrase ‘the early bird catches the worm’ can be found in every language on the planet,” Meadows says. “By contrast, there’s a huge stigma associated with being a night owl, as we live in a world that is, completely erroneously, set up for those of us who fare better in the morning.”
While people are only just starting to appreciate that point, the Covid-19 lockdowns have actually helped some night owls who’ve been obliged to work at home. “The fact that they haven’t had to get up early to commute means that they’ve been able to sleep in for a bit longer, which is more aligned to their natural rhythms,” Meadows explains.
This idea of alignment is important. For people whose lifestyles aren’t in harmony with their natural rhythms, any resultant sleep deprivation can harm their mental and physical health. Their concentration and memory can suffer and they may be vulnerable to higher levels of stress and anxiety. They may also be at greater risk of heart disease and type 2 diabetes. Studies indicate that night owls are more prone to all of these problems.
While most people require between six and eight hours of sleep a night, as many as half of all people in the West are “out of phase”, according to Dr Sarita Robinson, deputy head of psychology and computer science at the University of Central Lancashire. This means that they’re getting up before they want to or going to sleep later than they should. This is usually down to the effects on the suprachiasmatic nucleus of the blue light emitted by computer screens and mobile phones.
How to work with your body clock
So, what can people, and night owls in particular, do to improve their wellbeing? Meadows’ advice is to at least try to get the right amount of sleep most nights of the week.
“Keep a regular wake/sleep cycle,” he says. “If you’re incurring sleep debt from going to bed too late, take measures to repay it by going to bed earlier or sleeping later one night a week.”
Another factor that can benefit sleep-deprived people is to work effectively with light, says Dr Lindsay Browning, author of Navigating Sleeplessness and sleep ambassador for bed retailer And So To Bed. For night owls, this could mean opening the curtains first thing in the morning to get as much light into their eyes as possible. Doing so inhibits the production of melatonin, the sleep hormone, and activates cortisol, which makes them feel more awake. Sunrise alarm clocks, which wake people with a gradually brightening light, are a useful alternative during the darker winter months.
Meanwhile, larks who want to stay more alert in the evening should stimulate their brains with the blue light of an electronic device and refrain from dimming the lights in their homes.
Another option, Browning says, is for people to learn to work effectively with their own body clock and its natural peaks and troughs.
“It makes sense for larks to perform important tasks early in the day and for owls to save more complex activities for later,” she says. “While you can’t change your chronotype, you can recognise what it is and so make your day work more effectively for you.”