A regular bedtime for me is 2 a.m. As I’m writing this (at midnight, no less), I can already imagine the emotions evoked on the faces reading this: shock, horror, and maybe even a little judgement. I get it all the time, being a lifelong night owl. I’ve long been told my routine—sleeping from around 2 a.m. to 10 a.m.—is societally unacceptable and simply unsustainable, which piles onto the quiet guilt I sometimes feel for not working a “stable” job with regular hours. But as 2026 arrived, I decided I wanted to get to the bottom of whether I should be feeling bad about the way I manage my sleep; I’ve been like this for years, after all, and usually manage to make it work for me. So should I be trying to fix my circadian rhythm—and even if I wanted to, could I?
A quick refresher on what circadian rhythm is
Described as the body’s internal 24-hour biological clock, “it helps regulate many essential functions, including when we feel sleepy or alert, how hormones are released, body temperature, digestion, and even immune activity,” Alicia Gonzalez-Fernandez, MD, a specialist in family medicine at Imperial College London, tells SELF. “At the center of this system is a small group of nerve cells in the brain called the suprachiasmatic nucleus, which sits in the hypothalamus. This master clock responds primarily to light and darkness. When light enters the eyes—especially morning light—it sends a signal to the brain that it is daytime. This suppresses the release of the sleep hormone melatonin and promotes alertness. As light levels fall in the evening, melatonin rises, preparing the body for sleep.”
Many things can affect the circadian rhythm. These include—most notably—traveling across time zones (experiencing jet lag), the clocks going back or forwards, and daily changes to light exposure. Our individual clocks are, in part, predetermined by our genetics, but they’re also determined by our daily habits and environment. For many of us, that means our bed and wake-up times will vary depending on light exposure, when we eat, and how and when we exercise. Some of us run later (night owls) and others earlier (morning larks), which “are known as our chronotypes,” Allie Hare, MD, a consultant in sleep medicine and president of the British Sleep Society, explains to SELF. (My Oura ring likes to remind me that my chronotype is “late evening.”)
This suggests that with the right lifestyle tweaks, it’s possible to shift your circadian rhythm in a certain direction—should you wish to—which sleep experts tend to agree is correct. Start with a sleep diary, advises Dr. Hare, writing down what time you go to sleep and wake up each day and monitoring how this gradually alters amidst certain lifestyle changes. Light exposure habits top the list here. “Getting bright natural light soon after waking helps signal to the brain that the day has started, which anchors the body clock earlier. In contrast, reducing light exposure in the evening—especially from screens—allows melatonin to rise naturally and promotes earlier sleep onset,” explains Dr. Gonzalez-Fernandez.
