Study: Too much sitting linked to heart disease — even if you exercise

A recent study has suggested that sitting for over 10.6 hours a day increases heart disease risks — even among people who meet the recommended 150 minutes of moderate-vigorous physical activity (MVPA) per week.

In the study, published on Friday in the Journal of the American College of Cardiology, researchers found that sitting for a long period is linked with “future adverse cardiovascular outcomes, with particularly prominent effects on heart failure and cardiovascular mortality”.

A team of researchers in the Mass General Brigham health care system analysed activity-tracker data from 89,530 UK Biobank participants, examining sedentary behaviour’s impact on atrial fibrillation, heart attacks, heart failure, and cardiovascular death.

Participants wore a triaxial accelerometer on their wrists for over seven days to track movement. After a median 8-year follow-up, analysis revealed that risks for atrial fibrillation and heart attack steadily increased over time.

About 5% of study participants developed atrial fibrillation, 2.1% developed heart failure, 2% had a heart attack, and a little less than 1% died from cardiovascular-related causes.

“Our findings really emphasize the importance of avoiding excess sitting… whether or not you’re physically active,” said Ezim Ajufo, the first study author and a cardiology fellow at Brigham and Women’s Hospital in Boston.

“We would really recommend that as many people as possible avoid sitting more than 10.6 hours a day. That’s not a hard and fast threshold, but we think it’s a reasonable first step for guidelines and public health intervention.”

However, Ajufo said the research has some limitations. “The study is also observational, which means that while it can make associations, it can’t prove that sitting was the cause of the heart disease,” said the first study author.

The researchers recommended standing or walking for a few minutes every 30 to 60 minutes or transitioning between tasks with short walks.

“Exercise is critical, but avoiding excessive sitting appears separately important,” said Patrick Ellinor, the co-senior author, cardiologist and co-director of the Corrigan Minehan Heart Center at Massachusetts General Hospital.

“Our hope is that this work can empower patients and providers by offering another way to leverage movement behaviors to improve cardiovascular health.”

Also speaking, Shaan Khurshid, another co-senior author and an electrophysiologist and faculty member in the Telemachus And Irene Demoulas Family Foundation Center for Cardiac Arrythmias at Massachusetts General Hospital, said: “our data supports the idea that it is always better to sit less and move more to reduce heart disease risk, and that avoiding excessive sitting is especially important for lowering risk of heart failure and cardiovascular death”.

Keith Diaz, an associate professor of behavioural medicine at Columbia University Medical Center, who was not involved in the study, revealed that more research is needed to determine the specific risks and guidelines for what constitutes too much sitting.