Lounging around too much after a heart attack can set you up for another one, a new study says.

Within a year of being treated for heart attack symptoms, people who sat around afterwards for more than 14 hours a day on average were at greater risk for another heart-related health emergency, researchers reported May 19 in the journal Circulation: Cardiovascular Quality and Outcomes.

Those with the lowest activity levels had 2.5 times the risk of another heart problem or death within the following year, results show.

However, replacing sitting around with either movement or sleep can improve a person's odds, researchers found.

“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,” said lead researcher Keith Diaz, an associate professor of behavioral medicine at Columbia University Medical Center in New York City.

“More physical activity and more sleep are healthier than sitting, so we hope these findings support health professionals to move toward a more holistic, flexible and individualized approach for physical activity in patients after a heart attack or chest pain,” Diaz added in a news release.

For the study, researchers followed more than 600 people ages 21 to 96 who were treated for a heart attack or chest pain at the Columbia University Medical Center’s ER between 2016 and 2020.

The participants wore a wrist device that tracked their movements for a median of 30 days after their hospital discharge, allowing researchers to estimate their physical activity. (Median means half tracked longer, half for less time.)

Researchers tracked the people for a year following their ER visit, and compared how they fared to their average movement levels.

”Current treatment guidelines after a cardiac event focus mainly on encouraging patients to exercise regularly,” Diaz said. “In our study, we explored whether sedentary time itself may contribute to cardiovascular risk.”

Results showed that replacing a half-hour of sedentary time with a half-hour of moderate-to-vigorous physical activity every day reduced the risk of heart attack, stroke or death by 61%.

Likewise, replacing the same amount of sedentary time with light physical activity lowered risk by 50%.

Even replacing sedentary time with sleep lowered risk by 14%, results show.

“We were surprised that replacing sedentary time with sleep also lowered risk,” Diaz said. “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.”

These results provide “further support for a ‘sit less, move more’ strategy and – important for patients recently hospitalized for acute coronary syndrome who may have barriers to more intense exercise – found that increasing light-intensity activities by 30 minutes a day was related to dramatic reductions in the risk of a cardiac event within the next year,” said American Heart Association spokeswoman Bethany Barone Gibbs, chair of epidemiology and biostatistics at West Virginia University’s School of Public Health.