WASHINGTON (AP) — Being a night owl can be bad for your heart.That may sound surprising but a large study found people who are more active late at night — when most of the population is winding down or already asleep — have poorer overall heart health than the average person.“It is not like, that, night owls are doomed,” said research fellow Sina Kianersi of Brigham and Women’s Hospital and Harvard Medical School, who led the study. “The challenge is the mismatch between your internal clock and typical daily schedules ” that makes it harder to follow heart-healthy behaviors.And that’s fixable, added Kianersi, who describes himself as “sort of a night owl” who feels a boost in “my analytical thinking” after about 7 or 8 at night.Heart disease is the leading cause of death in the U.S. The American Heart Association has a list of eight key factors that everyone should heed for better heart health: being more physically active; avoiding tobacco; getting enough sleep and a healthy diet; and controlling blood pressure, cholesterol, blood sugar and weight.

Where does being a night owl come in? That has to do with the body’s circadian rhythm, our master biological clock. It follows a roughly 24-hour schedule that regulates not just when we become sleepy and when we’re more awake but also keeps organ systems in sync, influencing things like heart rate, blood pressure, stress hormones and metabolism.