Second Cardiac Event Risk Lowered by Spending Less Time Sitting

Researchers at Columbia University Medical Center say that patients recovering from heart attacks or chest pain can significantly reduce their risk of another cardiac event simply by spending less time sitting. The study, published in Circulation: Cardiovascular Quality and Outcomes, followed 609 adults treated in New York City hospital emergency departments for acute coronary syndrome, showed that replacing 30 minutes of sedentary time with 30 minutes of any form of physical activity, or 30 minutes of sleep, reduced the risk of heart attack, revascularization, or rehospitalization.

“Current treatment guidelines after a cardiac event focus mainly on encouraging patients to exercise regularly,” said the study’s lead author, Keith Diaz, PhD, an associate professor of behavioral medicine at Columbia University Medical Center. “In our study, we explored whether sedentary time itself may contribute to cardiovascular risk.”

After following patients from 2016 to 2020, the team’s analysis found that people in the most sedentary group—those averaging more than 14 hours of inactivity daily—were more than twice as likely to experience another cardiac event. Those with the lowest physical activity levels had a 2.58 times higher risk than the most active group.

“Sedentary behavior was associated with increased risk of one-year cardiac events/mortality among patients evaluated for acute coronary syndrome,” the researchers wrote. “Replacing sedentary behavior with sleep, light-intensity physical activity, or moderate-to-vigorous physical activity was associated with lower risk. These findings highlight reducing sedentary behavior as a potential strategy to improve posthospitalization outcomes.”

To determine the potential benefits of increased activity or additional sleep, the investigators used a method called isotemporal substitution analysis, which helps estimate the potential effects of replacing one form of activity with another. This analysis showed that replacing just 30 minutes of sedentary time with 30 minutes of moderate-to-vigorous physical activity was associated with a 61% reduction in the risk of a subsequent cardiovascular event or death. Substituting the same amount of time with light-intensity physical activity reduced risk by 50%, and replacing it with sleep led to a 14% risk reduction.

“We were surprised that replacing sedentary time with sleep also lowered risk. Sleep is a restorative behavior that helps the body and mind recover, which is especially important after a serious health event like a heart attack,” Diaz said. “Our study indicates that one doesn’t have to start running marathons after a cardiovascular event to see benefits. Sitting less and moving or sleeping a little more can make a real difference.”

The new research builds on this research group’s previous work, which demonstrated that patients recovering from heart attacks were sedentary for 12 to 13 hours per day on average. To track the activity of patients enrolled in the study, the Columbia team fitted them with wrist accelerometers to measure their forward-backward, side-to-side, and up-down motions. The data collected from the accelerometer allowed the researcher to infer the intensity of each person’s physical activity and provide more accurate data on the time each spent moving, as opposed to asking them to self-report their activity.

The accelerometer data revealed distinct differences between activity levels. The most active group averaged 25 minutes of moderate-to-vigorous activity and 143.8 minutes of light activity per day, with 11.7 hours spent sedentary. The least active participants averaged only 2.7 minutes of moderate-to-vigorous activity and 82.2 minutes of light activity per day, with 15.6 hours sedentary.

“This study found that replacing sedentary time with light intensity activities, like tidying up the house or strolling at a slow pace, was nearly as beneficial as moderate-to-vigorous intensity physical activities, like biking or doing aerobics,” said Bethany Barone Gibbs, PhD, a professor at West Virginia University and past chair of the American Heart Association’s Physical Activity Committee. “These findings suggest sitting less and doing anything else—like taking a walk, cooking, playing with your dog, or gardening—will help you stay healthier.”

The findings have the potential to significantly alter care recommendations for patients after a cardiac event. Current rehabilitation programs typically emphasize structured exercise, which is often inaccessible or intimidating for some patients. This study supports incorporating low-barrier strategies such as reducing sedentary time and encouraging light movement or adequate sleep as additional interventions.

While the researchers noted their study is one of the first to deploy accelerometers to measure active versus inactive time, they said there is the possibility that the devices may have overestimated active time. Other limitations of the research included the absence of socioeconomic and environmental data that could affect health outcomes, and the discharge destination data were not collected, which limits the ability to measure and assess the influence of different care settings on patient recovery.

Nonetheless, “our study indicates that replacing sedentary time with other behaviors may be an effective strategy for reducing risk of adverse outcomes,” the researchers noted.