Sitting for Over 10 Hours a Day: How It Increases Your Heart Disease Risk

TOPLINE:

Sedentary time over 10.6 hours a day increases the risk of atrial fibrillation, heart failure, myocardial infarction, and cardiovascular death, even among those who meet exercise guidelines.

METHODOLOGY:

• Researchers analyzed data from 89,530 middle-aged and older adults (average age 62, 56% female) from the UK Biobank using a validated machine learning method.
• Participants wore a wrist accelerometer for 7 days to track movement.
• The study classified activities as sleep, sedentary, light, or moderate to vigorous physical activity.
• Participants were monitored for an average of 8 years through national health databases in England, Scotland, and Wales.
• The average sedentary time was 9.4 hours per day.

TAKEAWAY:

• Over the follow-up period, 3,638 (4.9%) had atrial fibrillation, 1,854 (2.09%) developed heart failure, 1,610 (1.84%) faced myocardial infarction, and 846 (0.94%) died from cardiovascular causes.
• Atrial fibrillation and myocardial infarction risks increased with more sedentary time. A sedentary time over 10.6 hours showed a 11% higher risk for atrial fibrillation.
• Heart failure and cardiovascular death risks were low until sedentary time surpassed 10.6 hours, rising by 45% and 62%, respectively.
• Even those meeting physical activity guidelines but sedentary over 10.6 hours had a significant risk for cardiovascular death. Reducing sedentary time by 30 minutes lowered heart failure risk.

IN PRACTICE:

This study shows that sedentary behavior is a key factor in cardiovascular disease risk, even in physically active individuals.

SOURCE:

led by Ezimamaka Ajufo, MD, from Brigham and Women’s Hospital, published on November 15, 2024, in the Journal of the American College of Cardiology.

LIMITATIONS:

Wrist accelerometers may misclassify standing as sedentary. Activity data collected over one week might not represent long-term habits. The sample was mostly White and selected for higher health and socioeconomic status, which may limit the broader application of these findings.

DISCLOSURES:

The authors received support from institutions and pharmaceutical companies and served on advisory boards.