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April 12, 1993

Should Patients With Heart Disease Exercise in the Morning or Afternoon?

Author Affiliations

From the Section of Cardiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC.

Arch Intern Med. 1993;153(7):833-836. doi:10.1001/archinte.1993.00410070031004

Objective:  To compare the cardiovascular risk of exercise in the morning and afternoon in patients with established heart disease.

Design:  Retrospective cohort study. Patients: Patients with established heart disease referred for participation in a comprehensive cardiac rehabilitation program.

Intervention:  Supervised, submaximal exercise (1 hour three times per week) performed either in the morning (7:30 AM) or the afternoon (3 PM).

Main Outcome:  Documented cardiac events that occurred while patients were exercising in the rehabilitation programs.

Results:  There were five cardiac events in 168 111 patient-hours of exercise in the morning, with an incidence of 3.0±1.3 events per 100 000 patient-hours. There were two events during the 84 491 patient-hours of exercise in the afternoon, for an incidence of 2.4±1.5 events per 100 000 patient-hours (not significant). The risk ratio of cardiac events during exercise in the morning compared with the afternoon was 1.27 (95% confidence interval, 0.25 to 6.55).

Conclusion:  In patients with coronary artery disease, the incidence of cardiac events is low during regular, submaximal exercise whether performed in the morning or the afternoon.(Arch Intern Med. 1993;153:833-836)