No one crows louder than the proverbial “early bird”, boasting about their pre-work run to anyone who’ll listen. Night owls, on the other hand, often pride themselves on their bursts of productivity as they burn the midnight oil.
But a new study published in Nature Communications suggests that, rather than just these two camps, there are actually five “subtypes” of sleeper, determined by the parts of the day when people feel most alert or ready to sleep.
And, while previous studies have linked night owl tendencies to worse heart health and mental health, with early mornings viewed as the way to go for wellbeing, the latest findings from the team at McGill University in Canada question that – and suggest that the relationship between your sleep routine and your health might be more complex than you think. So which camp are you in – and what could it mean for your health?
The five types of sleeper
|
Type of sleeper |
Early bird or night owl |
Characteristics |
|
Subtype one |
Night owl 1 |
The first night owl pattern is associated with risky lifestyle behaviours, difficulties in emotional regulation and better cognitive performance. It’s also linked to lifestyle factors such as living with children, fast driving, mobile phone usage, alcohol consumption and smoking, as well as reduced sunlight exposure, suggesting late sleep and wake-up times. |
|
Subtype two |
Night owl 2 |
The second night owl pattern is associated with playing video games, lower incomes and lower participations in sports or exercise. It co-occurs with smoking, depression and variables related to cardiovascular risks or disease. |
|
Subtype three |
Early bird 1 |
The first early bird pattern is associated with education, non-smokers, rare alcohol intake, low risk-taking and fewer emotional issues. Those in this group will rise earlier, be more nervous and worry more, but don’t tend to have other emotional regulation issues. They also have a lower prevalence of health issues. |
|
Subtype four |
Early bird 2 |
The second early bird pattern is more female-biased and linked to depressive symptoms, antidepressant drug prescriptions, menstruation disorders and lower testosterone levels. |
|
Subtype five |
Night owl 3 |
The third night owl pattern is male-dominant and associated with cardiovascular risks, hair balding patterns and prostate diseases. This group is more prone to drinking, smoking, cannabis use, risk-taking behaviour, higher testosterone levels, depression and high blood pressure. |
What does your sleep type mean for your health?
Researchers identified the five subtypes of sleeper using brain imaging, questionnaires and medical records from more than 27,000 adults.
The first group of early birds – subtype three – had the fewest health problems overall, while the second group – subtype four – was closely tied to depression. This is contrary to previous research pointing to the fact that night owls have the worst health markers.
Among the night owls, subtype one performed better than all other groups in cognitive tests but had more emotional-regulation challenges. Subtype two showed risk-taking tendencies and a higher likelihood of heart problems, while subtype five was found to be more likely to have depression, smoke and face higher risks of heart disease.
“These subtypes are not defined only by bedtime or wake-up time,” says the study’s senior author Danilo Bzdok, associate professor in McGill University’s department of biomedical engineering. “They reflect a complex interaction of genetic, environmental and lifestyle factors.”
The study’s lead author, Le Zhou, a PhD student at McGill University, uses the term “biological diversity” to describe the findings. In other words, everyone is different, each chronotype subtype has its relative risks and perks, and there is no perfect sleep routine to suit all-comers.
Zhou hopes the study’s findings can move sleep profiles and advice away from a “one-size-fits-all approach”.
“In today’s digital and post-pandemic era, sleep patterns are more diverse than ever,” he says. “Understanding this biological diversity could eventually help inform more personalised approaches to sleep, work schedules and mental health support.”
The McGill University team’s next mission is using genetic data to determine whether someone’s chronotype subtype has biological roots from birth. If the results fall in the affirmative, you might be able to blame your bleary-eyed presence in any future 9am meetings on your parents.
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What can you do to improve your sleep?
The links between your sleep, schedule and health are still under investigation. However, if your sleep routine is rooted in genetics as suggested, finding a way to work with your body’s natural tendencies – rather than fighting them – is likely to deliver better health outcomes.
One of the biggest barriers to doing this is routine. In a world of biological diversity, humans are largely tarred with the same brush, expected to produce peak productivity between the hours of 9am and 5pm. This structure tends to reward early risers.
If you are naturally a night owl, overhauling your sleep schedule to suit this timetable is unlikely to feel fantastic. But there are things you can do to nudge your routine in this direction.
“Having a consistent bedtime and wake time is one of the absolute best things you can do, not only for your sleep but also your health,” says Emily Capodilupo, senior vice president of research, algorithms and data at wearable company WHOOP. “It reduces inflammation, reduces your risk of cancer and type 2 diabetes, and improves metabolic health.”
Establishing consistent cues ahead of your bedtime, such as dimming the lights in your home, changing into your pyjamas or reading in the hours before, aids this by sending clear signals to your body that it’s time to wind down.
Then, if you want to feel alert in the morning, going outside into daylight shortly after waking reinforces a rhythm in which your body is awake in the day and asleep at night.
“That can be as simple as making sure you open the blinds in the morning and let the sun hit your face,” Capodilupo continues. “It’s even better if you can actually get outside. Sunlight improves our mood, and tells your circadian rhythm that it’s time to wake up.”
Read more: Expert warns why this daily habit is shortening your life – even if you exercise
How much sleep should you get?
You need to sleep enough each night to support your health – approximately eight hours of sleep per 24 hours, according to Harvard Medical School’s division of sleep medicine. But this number can vary from six to nine hours depending on the individual, the institution reports.
Fortunately, there is a free and easy test to check if you’re getting enough sleep, according to human performance scientist and Absolute Rest founder Dr Andy Galpin.
“If I wake up feeling fully refreshed, I’m sharp, my energy is awesome, I train, I recover, I feel great, and then I’m sleepy at night – I don’t really care what any fitness tracker says,” he tells me.
“If your daytime function is really good then you probably don’t need to mess around too much with your sleep.”
It’s natural to start feeling a bit drowsy in the afternoon, he adds. Building “sleep pressure” throughout the day is necessary to help us sleep soundly at night.
However, if you find yourself struggling for energy throughout the morning, it could be time to consult his list of nine tips for a better sleep.
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