Can Your Chronotype Change? What the Research Says

By the ChronoSleep team · Updated October 23, 2026 · 6 min read

What decides your chronotype?

Your chronotype is the timing of your internal body clock: when your body releases melatonin, when your temperature and alertness rise, and when you naturally feel ready for sleep. That clock runs on a cycle of close to, but not exactly, 24 hours, so it has to be reset every day. Light is the main signal that resets it.

Genes set your starting point. The largest genetic study of chronotype so far, covering 697,828 people, found 351 regions of DNA linked to being a morning or evening person. The effect of any single gene is small, though: people carrying the most "morning" variants slept only about 25 minutes earlier than those carrying the fewest. Genes nudge you towards one end of the spectrum. Age, light and habits decide where you actually land.

Your chronotype changes with age

Age is the biggest natural shift most people go through. In a survey of around 25,000 people aged 8 to 90, Roenneberg and colleagues found a clear pattern:

• Children tend to be early types.
• Teenagers get steadily later, which is why many teens struggle with early school starts.
• Around age 20, sleep timing reaches its latest point. The researchers proposed this turning point as a biological marker of the end of adolescence.
• Through adulthood, timing gradually moves earlier again, and older adults are often early risers.

So a teenager who tested as a Wolf may test as a Bear in their thirties, and many people drift towards a Lion-like schedule later in life. That's also why the ChronoSleep quiz starts by asking your age.

Light can move your body clock

Modern life gives most people dim days indoors and bright evenings under lamps and screens. Both push the body clock later. Two camping studies show how much of a difference natural light makes:

• After a week of camping with only sunlight and campfire light, eight volunteers' body clocks (measured by melatonin timing) moved about two hours earlier than during their normal routine. The later chronotypes shifted the most.
• A follow-up study found that a single weekend of camping produced about 69% of the shift seen after a full week.

These were small studies, so the exact numbers shouldn't be taken too literally. The direction is clear, though: more daylight in the morning and less bright light at night moves your clock earlier, quickly.

Can a night owl become a morning person?

A night owl can become an earlier owl. In a 2019 study, 22 night owls were split into two groups. For three weeks, one group followed a simple routine: waking and going to bed 2–3 hours earlier, getting outdoor light in the morning, limiting light in the evening, keeping the same sleep times on work days and days off, and eating at set times. Their sleep and body clocks moved about two hours earlier without them sleeping less. They also reported less stress, fewer symptoms of depression and less daytime sleepiness, and their morning performance improved.

The catch is that the shift lasts only as long as the routine does. Go back to late nights and dim mornings, and your clock drifts back. You're moving your timing within your natural range, not swapping your chronotype for a different one.

What you can realistically change

1. Get daylight soon after waking. Outdoor light is far brighter than indoor light, even on a cloudy day. It's the strongest signal for moving your clock earlier.
2. Dim the evening. Lower the lights and screen brightness in the last hour or two before bed.
3. Keep the same wake time every day. Sleeping in for hours at the weekend pushes your clock later and makes Monday feel like jet lag.
4. Move in small steps. Shifting bedtime and wake time a little at a time is easier to stick with than one big jump.
5. Expect it to take weeks. In the study above the shift came from three weeks of consistency, not a few good nights.

Your type's free guide page has a ready-made evening wind-down and the mistakes to avoid: see Lion, Bear, Wolf or Dolphin.

When it's more than your chronotype

If you can't fall asleep until very late however consistent you are, and it's affecting your work or health, it may be a circadian rhythm sleep disorder such as delayed sleep–wake phase disorder rather than just a late chronotype. The same goes for waking very early with low mood, or feeling exhausted despite enough time in bed. These are worth raising with a doctor or a sleep specialist.