Can You Change Your Chronotype?
Chronotype isn’t fixed for life, but it’s also not something you can talk yourself out of by deciding to become a morning person. The honest answer sits in between: there’s a real, biologically set range for each person, and some real room to move within it.
What tends to shift on its own
Chronotype changes predictably across a lifetime without anyone doing anything deliberate. It trends later through childhood and adolescence, is often at its latest in the late teens and early twenties, and then gradually trends earlier through adulthood, continuing into older age. This is one of the more consistent findings in chronobiology, and it’s a large part of why a household with a teenager and a grandparent often has two people running on very different internal clocks without either one doing anything wrong.
What responds to deliberate effort
Within the range set by age and genetics, the main lever available is light exposure, because light is the primary signal the body’s clock uses to set itself:
- Morning light nudges the clock earlier. Getting outside, or near a bright window, in the first hour or so after waking is the most reliable tool for someone trying to shift toward an earlier schedule.
- Evening light nudges the clock later. Bright light late in the day — including screens — pushes in the opposite direction, which is part of why cutting evening screen brightness is common advice for anyone trying to move earlier, and part of why owls who spend evenings under bright light tend to drift even later over time.
- Consistency matters more than any single day. A clock reset by light works gradually, over days and weeks of a steady pattern, not instantly. Shifting bedtime by 15–30 minutes every few days, paired with consistent morning light, tends to work better than an abrupt, large change that’s hard to sustain.
What doesn’t move much
A strong owl is unlikely to become a genuine, energetic-at-dawn lark, and a strong lark is unlikely to become someone who thrives at 1 a.m., regardless of effort. The evidence for a large genetic component means there’s a real ceiling on how far a deliberate shift can go, and pushing past that ceiling usually just produces someone who’s forcing an earlier or later schedule while chronically under-slept — which tends to make the underlying problem, a poor fit between schedule and clock, worse rather than better.
A more realistic goal
Rather than aiming to flip from owl to lark or the reverse, the more achievable target is usually a modest shift — an hour or so — combined with narrowing the gap between weekday and weekend schedules (see the article on social jetlag). That’s normally enough to turn a schedule that feels like a constant fight into one that’s merely a little early or a little late, which is a much easier problem to live with.