New Study: Sitting Too Much Can Hurt Your Heart

A new study reveals that a sedentary lifestyle raises the risk of the most common heart diseases, even in individuals who meet recommended exercise guidelines.

A study by researchers at Mass General Brigham highlights that simply fitting in a workout after a long day of sitting may not be enough to counteract the harmful effects of sedentary behavior on heart health. The study defines sedentary behavior as waking activities with low energy expenditure, such as sitting, reclining, or lying down, excluding sleep.

Findings revealed that prolonged sedentary time is associated with an increased risk of heart disease, particularly heart failure and cardiovascular-related death. However, replacing sedentary time with other activities significantly reduces these risks.

The study also found that meeting recommended levels of moderate-to-vigorous physical activity alone may not be sufficient to lower cardiovascular risk if excessive sitting remains a part of daily life. These findings are published in the Journal of the American College of Cardiology.

“Many of us spend the majority of our waking day sitting, and while there’s a lot of research supporting the importance of physical activity, we knew relatively little about the potential consequences of sitting too much beyond a vague awareness that it might be harmful,” said lead author Ezimamaka Ajufo, MD, a cardiology fellow at Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system. “Sedentary risk remained even in people who were physically active, which is important because many of us sit a lot and think that if we can get out at the end of the day and do some exercise we can counterbalance it. However, we found it to be more complex than that.”

Study Findings and Health Risks

Ajufo’s team, which included researchers from across Mass General Brigham, analyzed one week of activity-tracker data from 89,530 individuals from the UK Biobank prospective cohort. They looked at associations between daily time spent sitting and the future risk of four common cardiovascular diseases: atrial fibrillation, heart attacks, heart failure, and death from cardiovascular causes. The team used a machine learning algorithm to classify sedentary behavior.

They found sedentary behavior was associated with higher risks of all four types of heart disease, with a marked 40-60 percent greater risk of heart failure and cardiovascular death observed when sedentary behavior exceeded 10.6 hours a day (not including hours spent sleeping). Many of the negative effects of sedentary behavior persisted even among those individuals who achieved the guideline-recommended >150 minutes of moderate-to-vigorous physical activity per week. For example, although the study found that the risk of atrial fibrillation and heart attacks could be mostly eliminated by engaging in physical activity, the excess risk of heart failure and cardiovascular death could only be partially offset by physical activity.

The Importance of Reducing Sedentary Time

“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 the risk of heart failure and cardiovascular death,” said co-senior author Shaan Khurshid, MD, MPH, an electrophysiologist and faculty member in the Telemachus And Irene Demoulas Family Foundation Center for Cardiac Arrhythmias at Massachusetts General Hospital, a founding member of the Mass General Brigham healthcare system.

The research team hopes these findings will help inform future guidelines and public health efforts. They would like future prospective studies to test the efficacy of public health interventions that help people reduce the number of hours they spend being sedentary and see how that affects cardiovascular health. Next, they plan to extend this research to investigate the impacts of sedentary behavior on a range of other diseases and for longer spans of time.

“Exercise is critical, but avoiding excessive sitting appears separately important,” said co-senior author Patrick Ellinor, MD, PhD, a 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.”

Reference: “Accelerometer-Measured Sedentary Behavior and Risk of Future Cardiovascular Disease” by Ezimamaka Ajufo, Shinwan Kany, Joel T. Rämö, Timothy W. Churchill, J. Sawalla Guseh, Krishna G. Aragam, Patrick T. Ellinor and Shaan Khurshid, 15 November 2024, Journal of the American College of Cardiology.
DOI: 10.1016/j.jacc.2024.10.065

Disclosures: Krishna G. Aragam receives sponsored research support from Sarepta Therapeutics and Bayer AG; he also reports a research collaboration with the Novartis Institutes for Biomedical Research. Patrick T. Ellinor receives sponsored research support from Bayer AG, IBM Research, Bristol Myers Squibb, Pfizer and Novo Nordisk; he has also served on advisory boards and/or consulted for Bayer AG.

Funding: Researchers were supported by the John S. LaDue Memorial Fellowship in Cardiovascular Medicine or Vascular Biology grant, the Walter Benjamin Fellowship from the Deutsche Forschungsgemeinschaft (521832260), a research fellowship from the Sigrid Jusélius Foundation, the National Institutes of Health (K23HL159262-01A1, 1K08HL153937, RO1HL092577, R01HL157635, and K23HL169839-01), the American Heart Association (19AMFDP34990046, 862032, 18SFRN34230127, 961045, and 2023CDA1050571), the President and Fellows of Harvard College (5KL2TR002542-04), and the European Union (MAESTRIA 965286).