Morning exercise may show larger heart benefits in new study

A study of roughly 14,500 people using Fitbit data found that exercising in the morning—especially between 7 a.m. and 8 a.m.—was associated with lower cardiometabolic risk and a 31% lower risk of coronary artery disease; the research will be presented at the American College of Cardiology meeting and has not yet been peer‑reviewed.

A new study reported links between the time of day people exercise and several measures of heart and metabolic health. Researchers analyzed about a year of health information from roughly 14,500 participants, including heart rate data collected by Fitbits. The study’s authors and outside experts noted biological rhythms as a possible explanation. The research is scheduled for presentation at the American College of Cardiology Annual Scientific Session and has not yet undergone peer review. Key findings: - The analysis used about one year of Fitbit and health data from roughly 14,500 people. - Participants who exercised in the morning showed lower rates of cardiometabolic disease risk factors, including type 2 diabetes, obesity, high blood pressure and high cholesterol. - Morning exercisers were reported to have a 31% lower risk of coronary artery disease compared with those who exercised later in the day. - The largest association was observed among people who exercised between 7 a.m. and 8 a.m. - The reported differences persisted even when total weekly exercise amounts were similar but occurred later in the day. - The study is set to be presented at the American College of Cardiology meeting and has not yet been peer‑reviewed. Summary: The study suggests morning exercise may be linked with lower cardiometabolic and coronary artery disease risk, with the strongest association reported for activity between 7 a.m. and 8 a.m. Undetermined at this time.