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Medically Reviewed by Dr. Joseph Krainin

Written by Jocelyn Zakri MPH, RRT, RPSGT, RST

Chronotypes. It sounds fancy, but it’s really just a term for whether you’re a night owl or an early bird.

In zoology the word chronotype refers to the time (“chrono”) of the sleep and regular activities of an animal. For instance, nocturnal animals are active at night, while humans are diurnal – active in the day and asleep at night.

It’s important to note that your chronotype refers to more than just your rising and bedtime. It’s your body’s natural “timeline” for the various primal activities you would do during the day, such as eating, sleeping, and having sex.

If you’re a night owl, you now have an answer for why you feel so “out of whack” with the rest of society. Keep reading to learn more about chronotypes, how they work, and how to make your specific chronotype work for you – instead of against you.

How chronotypes work

Chronotypes have a genetic basis and are linked specifically to your PER3 gene. Your chronotype is tied to your circadian rhythms and your internal body clock.

Early birds have longer PER3 genes, while night owls have shorter ones. In addition to your wake- and bedtimes, the length of your PER3 gene also dictates how much sleep you need.

Early birds and night owls are the big names when it comes to chronotypes, but they’re not the only ones. Some sleep researchers argue that there are four main chronotypes, instead of two:

  • Bears tend to sleep and wake according to the sun, feeling most energetic during the daytime and having no trouble falling asleep at night. Their peak productivity occurs in the mid-morning and dips during the mid-afternoon slump. They represent 50% of the population.
  • Wolves (also known as night owls) go to sleep and wake later than others. Their peak productivity happens in the middle of the day and in the evening after everyone else has already logged off. Wolves represent 15-20% of the population.
  • Lions (also known as early birds) wake up early and are most productive in the morning. They get most of their productivity in before noon, so they’re naturally tired by the evening and go to sleep early. Lions represent 15-20% of the population.
  • Dolphins are light sleepers who have difficulty following a regular sleep routine due to more frequent nighttime awakenings. Their most productive in the mid-morning to early afternoon. Dolphins represent 10% of the population.

Sleep researcher Dr. Michael Breus popularized the theory of four chronotypes in his 2016 book The Power of When, although Russian researchers confirmed similar findings in 2015.

Chronotypes and sleep disorders

Some people are morning larks and rise early and are more active in the morning. Others are night owls and sleep late, being more active in the evenings and late nights. These are people at the poles; there are other variations such as people who rise early but do not become active until mid-morning, etc. Night owls also tend to sleep more on weekends, apparently having built up a sleep debt during the week more than larks do due to work and school schedules that do not correspond with their sleep preferences. If you are unsure which category you fall into, you can take an eveningness-morningness questionnaire to get a better idea.

When these tendencies are very strong and interfere with the person’s daily life, the person can be said to have a circadian rhythm sleep disorder. The two most common types include:

  • Advanced sleep phase syndrome (ASPS), which describes those with a circadian rhythm that is shifted much earlier. These extreme early birds, for example, may tire around 7 and wake up at 2 in the morning.
  • Delayed sleep phase syndrome (DSPS) describes those on the opposite end of the circadian spectrum, who tire and wake much later than others.

In either of these scenarios, the problem is not troubled sleep. Sleep, when they do get it, is fine. Rather, it is the problems it causes in their daily functioning and well-being. They often have to cut their sleep short to attend social and work functions, or they worry they have insomnia because they can’t sleep when others are sleeping.

If you lived on your own with no interactions with others, you wouldn’t have problems with your chronotype. Tension comes when you have to live and work with others. Even without a disorder like ASPS or DSPS, individuals, especially night owls, have to adjust to get to work at the time their employer demands and when social activities with others are scheduled – whether or not it corresponds to their peak energy times.

This disconnect is called social jet lag. Unlike real jet lag, the social form is chronic.

Changing your chronotype

Can you change from a morning lark to a night owl or vice versa? No. You can’t really change the underlying biological predilection to a chronotype. Over time your body may change. Lots of people find themselves turning into morning people as they age.

But you cannot accelerate the process or force a change. You can do things like use exposure to bright light to attempt to reset your circadian clock. And you can use a supplement like melatonin to help you fall asleep earlier, but this probably isn’t a good long term solution. Talk to a doctor. Most doctors will tell you to avoid staying on drugs for long periods unless necessary. Chronotherapy has been used effectively for circadian rhythm sleep disorder, delayed sleep phase type. This technique involves progressively delaying the sleep schedule until the desired bed and rise times are achieved.

Although, we all undergo a circadian shift during our teenage years. In adolescence, our circadian rhythms shift to later in the evening. Unfortunately, this shift coincides with more academic and extracurricular responsibilities – and extremely early school start times. To counteract the negative effects this has on teen’s mental, social and physical well-being, many sleep researchers have advocated for later start times.

Living with your chronotype

Chronotype behavior isn’t just seen in sleep times, but in your level of activity and vigilance during waking periods. Your chronotype even affects your body temperature, serum cortisol levels, and blood pressure. For example, morning larks experience an earlier circadian rhythm temperature peak than night owls.

We still very much live in an early bird’s world. People see early birds as ambitious go-getters, while night owls are considered lazy. Important meetings are scheduling for the morning hours and offices and schools expect you to be in and paying attention early in the day. However, there is some consolation for night owls:

  • Night owls tend to have higher incomes than early birds, according to a 1998 study.
  • One 1999 study found that night owls were actually more intelligent, even when tested in the morning hours.
  • Night owls have more sex (perhaps due to our association of sex as a nighttime activity).
  • Night owls can stomach caffeine better. Their nighttime sleep is less disrupted by daytime caffeine consumption than for morning people.
  • Night owls are even better at playing baseball.

However, night owls are also much likelier to engage in substance abuse like alcohol and smoking than early birds, and they also tend to be less happy. Researchers suspect this is due to the chronic social jet lag they suffer.

How to make your chronotype work for you

Your chronotype is your body’s natural sleep-wake cycle. If you try to work against this, you’ll not only have a tougher time falling asleep at night or staying awake during the day, but you’ll also experience more disturbed sleep.

Instead of fighting your chronotype, lean into it. Go to sleep when you’re tired, instead of forcing yourself to stay up later or go to bed earlier (depending on your chronotype). Schedule your most important meetings during your peak productivity times. Suggest fun activities to attend with friends and family during the hours that work best for you.

Most of all, stop giving yourself a hard time about your chronotype. Whether you are an early bird or a night owl, it doesn’t say anything about your value as a person. It simply explains your body’s natural sleep-wake cycle.

If you’d like help planning your daily routine based on your chronotype, Business Insider put together this helpful infographic based on the research of Dr. Michael Breus:

chronotypes infographic

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