Approximately 10 hours or more of sedentary behavior per day is associated with heightened risk of heart failure and cardiovascular death, even in those who regularly exercise.
More time spent sitting, reclining or lying down during the day may increase the risk of cardiovascular disease (CVD) and death, according to a study in JACC, the flagship journal of the American College of Cardiology, and presented at the American Heart Association's Scientific Sessions 2024.
More than 10-and-a-half hours of sedentary behavior per day was significantly linked with future heart failure (HF) and cardiovascular (CV) death, even among people meeting recommended levels of exercise.
"Our findings support cutting back on sedentary time to reduce cardiovascular risk, with 10.6 hours a day marking a potentially key threshold tied to higher heart failure and cardiovascular mortality," said Shaan Khurshid, MD, MPH, a cardiologist at the Massachusetts General Hospital and co-senior author of the study. "Too much sitting or lying down can be harmful for heart health, even for those who are active."
Insufficient exercise is a known risk factor for cardiovascular disease (CVD). Over 150 minutes of moderate-to-vigorous physical activity per week is recommended by current guidelines to promote heart health. However, study experts say exercise is only a small fraction of overall daily activity, and the current guidelines don't provide specific guidance on sedentary behavior which accounts for a much larger portion of daily activity, despite evidence that it's directly linked with CVD risk.
This study examined the amount of sedentary time at which CVD risk is greatest and explored how sedentary behavior and physical activity together impact the chances of atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI) and CV mortality.
Among the 89,530 study participants of the UK biobank, the average age was 62 years and 56.4% were women. Participants submitted data from a wrist-worn triaxial accelerometer that captured movement over seven days. The average sedentary time per day was 9.4 hours.
After an average follow-up of eight years, 3,638 individuals (4.9%) developed incident AF, 1,854 (2.1%) developed incident HF, 1,610 (1.84%) developed indecent MI and 846 (0.94%) died of CV causes, respectively.
The effects of sedentary time varied by outcome. For AF and MI, the risk increased steadily over time without major shifts. For HF and CV mortality, increase in risk was minimal until sedentary time exceeded about 10.6 hours a day, at which point risk rose significantly, showing a "threshold" effect for the behavior.
For study participants who met the recommended 150 minutes of moderate-to-vigorous physical activity or more, the effects of sedentary behavior on AF and MI risks were substantially reduced, but effects on higher risk of HF and CV mortality remained prominent.
Future guidelines and public health efforts should stress the importance of cutting down on sedentary time. Avoiding more than 10.6 hours per day may be a realistic minimal target for better heart health.
The use of wearable accelerometers has shown that exercise is significantly over-estimated by self-report and sedentary behavior is under-estimated. Replacing just 30 minutes of excessive sitting time each day with any type of physical activity can lower heart health risks. Adding moderate-to-vigorous activity cut the risk of HF by 15% and CV mortality by 10%, and even light activity made a difference by reducing HF risk by 6% and CV mortality by 9%.
This study adds to the growing evidence of a strong link between sedentary behavior and cardiovascular health. The findings strongly suggest that we need to get people moving to promote better health!
Reference:
Ezimamaka Ajufo, Shinwan Kany, Joel T. Rämö, Timothy W. Churchill, J. Sawalla Guseh, Krishna G. Aragam, Patrick T. Ellinor, Shaan Khurshid. Accelerometer-Measured Sedentary Behavior and Risk of Future Cardiovascular Disease. Journal of the American College of Cardiology, 2024; DOI: 10.1016/j.jacc.2024.10.065
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