Key points from article :
A recent study published in JACC, the flagship journal of the American College of Cardiology, highlights that spending too much time sitting or lying down increases the risk of cardiovascular disease (CVD) and death, even for individuals who meet recommended exercise guidelines. The research, presented at the American Heart Association’s Scientific Sessions 2024, identified a critical threshold: spending more than 10.6 hours a day in sedentary behaviour significantly elevates the risk of heart failure and cardiovascular mortality.
Dr. Shaan Khurshid, a co-senior author from Massachusetts General Hospital, emphasized that while regular exercise is important, it accounts for only a small portion of daily activity. Sedentary behaviour, which dominates much of people’s time, is a largely overlooked risk factor in current guidelines. This large-scale study of over 89,000 UK Biobank participants found that while exercise reduces risks for some conditions like atrial fibrillation and myocardial infarction, the harms of prolonged sitting on heart failure and cardiovascular mortality persist, even in active individuals.
The data, collected using wrist-worn accelerometers, revealed a "threshold" effect: risks for heart failure and cardiovascular death rose sharply after 10.6 hours of daily sedentary time. Importantly, replacing just 30 minutes of sedentary time with any physical activity—light or vigorous—was shown to reduce heart failure and cardiovascular mortality risks by up to 15%.
The findings suggest that future health guidelines should not only promote exercise but also explicitly limit sedentary time. Experts like Dr. Charles Eaton and Dr. Harlan Krumholz support the call for more movement, noting that wearable technology provides a clearer picture of activity patterns than self-reports. However, the study’s limitations, including the potential misclassification of activities and other confounding factors, point to the need for further research to refine these recommendations.
