Need to know
There’s no shortage of proclamations about the merits of starting your day early. Aristotle called rising before daylight a ‘healthy habit’, Marcus Aurelius offered a pep talk for getting up when you don’t feel like it, and Benjamin Franklin, known for his sage aphorisms, advised: ‘Early to bed, and early to rise, makes a man healthy, wealthy and wise.’ Today, CEOs regularly attribute their successes, in part, to setting their alarms for before 6am. And, of course, there’s the classic about the bird who gets the worm.
But maybe for you, rising with the sun doesn’t come so easily. Or, perhaps you have little trouble with mornings, but struggle with activities or responsibilities later in the day. People vary significantly in the times at which they wake up feeling refreshed or get sleepy at night. This is called your chronotype: your disposition to start your day earlier or later.
The types you are probably most familiar with are the early bird (or lark), who prefers an early morning wake up and is most inclined to be active early in the day, and the night owl, who favours a late wake time and increased activity in the evening or night. But chronotypes fall all along a spectrum, encompassing very early risers, very late risers, and everyone in between, says Roberto Refinetti, head of the Circadian Rhythm Laboratory at the University of New Orleans.
Each of us has a chronotype because of the body’s circadian rhythm, or how it has adapted to living with a 24-hour day that has light and dark periods. Our bodies aren’t programmed to do the same thing at every minute of the day – we have to trade off between sleeping, moving around, eating and so on, and these require different physiological conditions. We have biological clocks that manage hormonal levels, body temperature, heart rate, metabolism, hunger levels and more, depending on the time. One way to viscerally sense the presence of your circadian rhythm is to travel to a different time zone: jet lag is a mismatch between your body’s clock and the time in the outside world.
Just as mechanical clocks don’t all tick in exactly the same way, each person’s internal clock is at least a little bit different. Some clocks run faster or slower than others, and that’s where chronotypes emerge. Your chronotype reflects your personal wake and sleeping preferences, but it’s also a way of describing how your circadian rhythm compares with other people’s.
Why it’s helpful to work with your chronotype
It can be difficult when your chronotype doesn’t match up with your life – if your natural preferences about when you’d like to be tucked into bed or wake up in the morning don’t jibe with your work schedule or social engagements. It’s OK to live out of sync with your chronotype sometimes, but there can be consequences if you do it for too long.
The first thing you’ll likely notice is that you feel tired when you’re supposed to be fully awake, or you might have a hard time sleeping at night. Over time, as researchers know from studying overnight shift workers and others, people who experience chronic circadian misalignment may have an increased risk of various kinds of illness, from depressive symptoms to cardiovascular disease. ‘This risk decreases the less out of sync you are, but there is some evidence emerging now that there might still be an increased risk with being a few hours out of step,’ says Priya Crosby, a postdoctoral fellow studying circadian biology at the University of California Santa Cruz.
This Guide is not meant to pressure you into becoming a morning person or adopting any other chronotype – the opposite, in fact. I spoke to chronobiology experts about how to best understand what your chronotype is and to live in accordance with it, even if that means leaving the worms for the early birds.
What to do
Figure out your chronotype
In order to make your chronotype work for you, you first need to have a sense of what yours is. Chronotypes depend both on our genes and on our environment, though genes likely play a stronger role, Refinetti says. This means that your chronotype is fairly stable from day to day.
A simple way to learn about your chronotype is to ask yourself what time you would prefer to go to sleep and wake up if you had no other obligations, such as having to get up for work or school. If there is a period of days (eg, during a vacation), when you can simply go to sleep when you’re tired, and then wake up with no alarm clocks, do it – and record the times when you fall asleep and get up.
You may find it useful to have some rough categories for thinking about your chronotype. Michael Breus, a clinical psychologist and a fellow of the American Academy of Sleep Medicine, describes four chronotypes in his book The Power of When (2016):
- Traditional early birds, whom he calls lions. They wake up early, often around 5am, and feel most energetic before noon.
- Bears, those who still get up in the morning as it gets light outside, but later than the lions. Their peak productivity hours are between 10am and 2pm.
- Night owls, or wolves as Breus calls them, are later risers. They might feel energetic rushes into the evening, and their bedtimes are often midnight or later.
- Dolphins are his category for problem sleepers who have disorganised sleep habits and don’t feel aligned with any of these types.
Still, it’s important to remember that chronotypes are on a spectrum; people can vary by degrees and don’t all fit into a few groupings. ‘Although some people have made arbitrary cuts in the continuum, there are not distinct categories,’ Refinetti says. And, just like with height, there is a normal distribution of the trait, with most people in the middle of a bell curve and the rest along the two tails. Some people wake up very early, some very late, and most people are somewhere in between. In the United States, the most common wake-up times are around 7am, Refinetti says. ‘But about 1 per cent wake up as early as 4am, and 1 per cent as late as 12 noon,’ he adds.
If one of the animal types appeals to you, feel free to use that. If not, you could instead think about whether you gravitate more generally towards morningness or eveningness. ‘Most people do have a surprisingly accurate internal sense of what their chronotype might be,’ Crosby says. For more precision, there are scientifically tested questionnaires you can use, including the Morningness-Eveningness Questionnaire.
Find your best time of day
Once you’ve determined whether your chronotype leans more toward the morning or evening, you can put this information to use. You might find that you’re more alert at certain times of day compared with others. Circadian rhythms influence almost all aspects of human physiology, and you’re probably at your best during those periods when you feel most awake. This even applies to physical activity: Crosby says that athletes with an earlier chronotype perform better on standardised fitness tests that are conducted in the morning, compared with athletes with a later chronotype.
Imagine that you had to do a complicated work assignment or a physically demanding task. If you could pick your ideal time of day to do it, when would that be? Try to schedule more complex or challenging tasks in the windows of time that align with your type. ‘I have a later chronotype and, correspondingly, find that I am most alert and focused and do my best writing and thinking in the afternoon,’ Crosby says.
This is quite different from advice that suggests simply getting up early in order to access new levels of productivity or focus. That might work for some people, but probably those who are already ‘morning people’ to some degree.
‘I suggest that most people identify their chronotype, and then try to live as close to it as possible,’ Breus says. He also proposes that, if there’s a time of day when you’re most alert, more effective, perhaps even nicer to be around, then family members, bosses and friends may be motivated to help you live closer to your preferred schedule. For example, a boss might allow you to come into work an hour earlier or later, and shift your workday accordingly. Spouses or parents may be more understanding about later wake-up times or earlier bedtimes.
Breus often asks people to try, for one week, getting up at a time when they actually want to and then seeing how that seems to impact other activities and behaviours during the day. ‘They always seem to love it,’ he says.
Play with your zeitgebers
Sometimes you just can’t make your schedule match your preferred sleep and wake times, or at least not completely. In that case, tweaking your use of zeitgebers could help your body feel more adjusted.
Though you have an internal clock that ticks away on its own, it is also responsive to external cues. Those cues are known as zeitgebers (which translates to ‘time giver’), and they include any indications of time from the outside world that your body might use to help regulate itself.
Light is a powerful zeitgeber. In 2017, researchers sent people camping in the Rocky Mountains of Colorado to see if it would adjust their circadian rhythms. Each person slept in their tent whenever they wanted to, and they were exposed to only natural light, including sunlight, moonlight and campfires. They had no flashlights or mobile phones. When they got back, they underwent a 24-hour assessment that found that the onset of their melatonin (a hormone related to sleep) was much earlier than before the camping trip, and closer to sunset. Similarly, a previous summertime camping study found evidence that ‘after exposure to only natural light, the internal circadian clock synchronises to solar time’, starting preparations for sleep closer to sunset and for awakening closer to sunrise.
You can use deliberate exposure to this zeitgeber to feel more awake during the day. For all, but especially later chronotypes, seeing sunlight first thing in the morning can be helpful. ‘If my patients feel sleepy during the day due to being “off” their chronotype, I ask them to use sunlight at 2-3pm for 15 minutes to help re-energise them, and go for a walk for 15 minutes,’ Breus says.
Food and physical activity are also considered zeitgebers. Exercising can increase some hormones, such as cortisol, that make you feel more awake. You might be able to adjust your sleep or wake times slightly by timing these events appropriately. ‘If you want to go to sleep and wake up earlier, it might help to be more active, eat more of your food and see more light earlier in the day,’ Crosby says. ‘And to avoid these things particularly in the couple of hours before you want to sleep.’
Beware social jetlag
When you travel to a distant time zone, you may suffer from jet lag for a few days until you adjust. But there’s a similar kind of disruption that can happen right where you live, and that can reoccur every week. ‘Social jetlag’, a term coined in 2006, describes a misalignment of biological time and ‘social time’, which includes one’s schedules related to school or work.
If you’re someone with a late chronotype, not only are you likely asked to do work or other tasks at hours that are ‘off-peak’ for you, but you’re probably sleep deprived. This might mean that, during the week, you get up earlier than you’d like, but then sleep in late on the weekends. Social jetlag can happen for early birds, too, such as when they stay up later than they’d prefer to hang out with friends on Friday and Saturday, but not on other nights. Studies have found that the consequences of chronic social jetlag may include increased tobacco, caffeine and alcohol consumption, depression risk, heart risks, risk of metabolic disorders, and simply not feeling your best, most alert self.
The best way to avoid the downsides of social jetlag is to try to wake up around the same time each day and to go to bed roughly around the same time each night. Consider any adjustments that might be useful for making this happen, such as setting clearer expectations with other people about how late you’re willing to stay out each weekend (barring some special occasions), or figuring out a time to wake up on workdays at which you can also wake up on weekends. Some smartphones have a feature that can track your wake and sleep times to help remind you to start to get ready for bed, or when to wake up.
The Spanish Roman Catholic priest Saint Josemaría Escrivá wrote about a concept called the ‘heroic minute’, or the exact minute at which a person should wake up each day. He meant it as a devotional and ascetic practice, and focused on a time early in the morning. But your heroic minute can be any time that works for you, as long as it’s a set time at which you resolve to rise, as he advised, ‘without hesitation’.
Be considerate of others’ chronotypes
If you’re asking others to let you adjust some of your work, socialising or other activities to the times that are optimal for you, then it only makes sense to offer the same in return. This requires having a little bit of flexibility if things don’t happen right on your schedule. If you talk to your friends, partner or co-workers about their chronotypes and what works best for them, perhaps they will be more open to respecting your preferences, too.
Being considerate about chronotypes also includes avoiding hasty judgments about what kinds of personality traits or dispositions people with certain chronotypes have. Research has found that people think of ‘night owls as significantly more lazy, unhealthy, undisciplined, immature, creative, and young’. Especially if you’re a boss, manager or teacher, check your assumptions about what it means that a person struggles with the early hours. This attitude can go a long way toward accepting your own chronotype too. Leaning towards a later wake-up doesn’t mean you’re lazy, just like preferring to go to sleep earlier doesn’t mean you’re no fun.
One recent development that seems to reflect an increased sensitivity to chronotype is the call to start schooldays later, since teens are in a phase of life when a later chronotype is typical, and expecting them to complete schoolwork early in the morning isn’t setting them up for success. ‘People who start the day early also end the day early,’ Refinetti says. ‘They are not more hard-working than people who start the day later and end the day later.’
Key points – How to embrace being a lark or an owl
- People naturally vary on when they prefer to start the day. Your chronotype reflects your disposition to wake up and go to sleep earlier or later, and the times when you are most inclined to be active.
- It’s helpful to work with your chronotype. Living out-of-step with your chronotype may make it harder to feel awake during the day or to get to sleep when you’d like to. In the long term, it could also have health consequences.
- Figure out your chronotype. Consider what times you would prefer to go to sleep and to wake up if you had no other obligations. You might find it useful to compare your experience to a handful of chronotype categories or to take a questionnaire for more precision.
- Find your best time of day. Plan to take on more complex or challenging tasks during periods of the day when you tend to be most awake (eg, later in the day rather than in the morning, if you have a later chronotype).
- Play with your zeitgebers. Increasing your exposure to sunlight at times of the day when you tend to be sluggish can help you feel more awake. And if you want to fall asleep and wake up earlier, consider shifting physical activity and eating to earlier hours.
- Beware social jetlag. A mismatch between your schedules on schooldays/workdays and on free days could be costly, so try to maintain a consistent sleep-wake timing throughout the week.
- Be considerate of others’ chronotypes. Be conscious of and flexible about other people’s sleeping and waking preferences; it could help you to develop mutual chronotype respect.
How chronotypes change with age
You might remember being a teenager who easily slept until noon, after having stayed up late into the night. But if you’re older, you may have a hard time sleeping past 9am. This is because a person’s chronotype can change a lot throughout the lifespan.
Younger children tend to have earlier chronotypes, which progressively move later until the late teens and early 20s. One study, based on data from the American Time Use Survey, with participants aged 15 and older, found that more than 50 per cent of chronotype change happened during adolescence and early adulthood; the largest differences were seen between people aged 15 and 25. There was a ‘peak in “lateness”’ at around age 19. Chronotypes typically shift earlier again as people get older, a development that continues into middle age and beyond.
It’s not entirely clear why these trends happen. They could reflect changes in the way that circadian genes or parts of the brain function, how people take in cues from the environment, and/or lifestyle-related shifts. But it’s something to remember as you assess your own chronotype: if you’re in a transitional period, your chronotype may naturally be shifting.
Research does vary somewhat on the typical timing of these transitions. In one study of more than 25,000 German children and young adults, the turn back towards morningness happened, on average, around 15.7 years in girls, and 17.2 years in boys. A study from 2004 found that the midpoint of sleep gets later starting at 10 years old, until around 20, before starting to shift earlier. The authors of the latter study suggested that the movement of a person’s chronotype back toward an earlier one could be a biological indication of the ‘end of adolescence’.
Social jetlag seems to cause the most problems for teenagers: more than 80 per cent of public schools in the US start classes at 8:30am or earlier. Based on a study from 2017, the midpoint of an average 17- or 18-year-old’s sleep is 4:30am, suggesting that ‘senior high-school students get up and go to school in their biological night’.
Living in harmony with your chronotype as an adult requires asking other people for some consideration, and the same can be granted to teens, too. In the autumn of 2016, Seattle’s public schools announced that they would change the start times of their classes. Elementary schools (which had the latest start times) would begin earlier, but middle and high schools would shift to around an hour later, beginning at 8:45am instead of 7:50am. This seemingly small shift quickly had an impact: in 2018, a study in Science showed that these later start times were associated with more sleep for the students, a 4.5 per cent increase in median grades, and better attendance.
Links & books
If you found the animal chronotypes intriguing, you can take Michael Breus’s chronotype quiz to find out if you’re more of a dolphin, lion, bear or wolf.
In this brief video ‘Social Jetlag and its Consequences’ (2012), Till Roenneberg, a professor of chronobiology at Ludwig-Maximilians University Munich, explains the phenomenon and its negative consequences.
To learn more about the biology of circadian rhythms, check out the article ‘Medicine Nobel Awarded for Work on Circadian Clocks’ (2017), published in Nature, on the three Nobel Prize recipients who discovered ‘circadian clock genes’.
Is there something more moral about mornings and getting up early? Some research has suggested as much, but the New Yorker article ‘No, Mornings Don’t Make You Moral’ (2015) by Maria Konnikova challenges the idea.