Sitting for More Than 10 Hours Daily Ups Heart Disease Risk

TOPLINE:

Sedentary time exceeding 10.6 h/d is linked to an increased risk for atrial fibrillation, heart failure, myocardial infarction, and cardiovascular (CV) mortality, researchers found. The risk persists even in individuals who meet recommended physical activity levels.

METHODOLOGY:

• Researchers used a validated machine learning approach to investigate the relationships between sedentary behavior and the future risks for CV illness and mortality in 89,530 middle-aged and older adults (mean age, 62 years; 56% women) from the UK Biobank.
• Participants provided data from a wrist-worn triaxial accelerometer that recorded their movements over a period of 7 days.
• Machine learning algorithms classified accelerometer signals into four classes of activities: Sleep, sedentary behavior, light physical activity, and moderate to vigorous physical activity.
• Participants were followed up for a median of 8 years through linkage to national health-related datasets in England, Scotland, and Wales.
• The median sedentary time was 9.4 h/d.

TAKEAWAY:

• During the follow-up period, 3638 individuals (4.9%) experienced incident atrial fibrillation, 1854 (2.09%) developed incident heart failure, 1610 (1.84%) experienced incident myocardial infarction, and 846 (0.94%) died from cardiovascular causes.
• The risks for atrial fibrillation and myocardial infarction increased steadily with an increase in sedentary time, with sedentary time greater than 10.6 h/d showing a modest increase in risk for atrial fibrillation (hazard ratio [HR], 1.11; 95% CI, 1.01-1.21).
• The risks for heart failure and CV mortality were low until sedentary time surpassed approximately 10.6 h/d, after which they rose by 45% (HR, 1.45; 95% CI, 1.28-1.65) and 62% (HR, 1.62; 95% CI, 1.34-1.96), respectively.
• The associations were attenuated but remained significant for CV mortality (HR, 1.33; 95% CI: 1.07-1.64) in individuals who met the recommended levels for physical activity yet were sedentary for more than 10.6 h/d. Reallocating 30 minutes of sedentary time to other activities reduced the risk for heart failure (HR, 0.93; 95% CI, 0.90-0.96) among those who were sedentary more than 10.6 h/d.

IN PRACTICE:

The study “highlights a complex interplay between sedentary behavior and physical activity, ultimately suggesting that sedentary behavior remains relevant for CV disease risk even among individuals meeting sufficient” levels of activity, the researchers reported.

“Individuals should move more and be less sedentary to reduce CV risk.…[B]eing a ‘weekend warrior’ and meeting guideline levels of [moderate to vigorous physical activity] of 150 minutes/week will not completely abolish the deleterious effects of extended sedentary time of > 10.6 hours per day,” Charles B. Eaton, MD, MS, of the Warren Alpert Medical School of Brown University in Providence, Rhode Island, wrote an editorial accompanying the journal article.

SOURCE:

The study was led by Ezimamaka Ajufo, MD, of Brigham and Women’s Hospital in Boston. It was published online on November 15, 2024, in the Journal of the American College of Cardiology.

LIMITATIONS:

Wrist-based accelerometers cannot assess specific contexts for sedentary behavior and may misclassify standing time as sedentary time, and these limitations may have affected the findings. Physical activity was measured for 1 week only, which might not have fully represented habitual activity patterns. The sample included predominantly White participants and was enriched for health and socioeconomic status, which may have limited the generalizability of the findings.

DISCLOSURES:

The authors disclosed receiving research support, grants, and research fellowships and collaborations from various institutions and pharmaceutical companies, as well as serving on their advisory boards.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.