A new research presented at the American Heart Association’s Scientific Sessions 2024 reveals that spending more than 10.6 hours a day sitting or lying down increases the risk of cardiovascular disease (CVD) and death. Even individuals who meet the recommended physical activity guidelines are at risk if they spend too much time sedentary.
The study, published in the Journal of the American College of Cardiology (JACC), highlights a significant link between extended sedentary behavior and heart failure (HF) and cardiovascular death. Sitting or reclining for more than 10.6 hours daily marks a critical threshold, beyond which the risks of these conditions rise substantially.
EXERCISE DOESN’T OFFSET THE IMPACT OF SEDENTARY TIME
Exercise is crucial for heart health. Still, the study underscores that it can’t fully negate the dangers of excessive sitting. “Too much sitting or lying down can harm heart health, even for those who are active,” said Dr. Shaan Khurshid, a cardiologist at Massachusetts General Hospital and co-senior author of the study.
WHAT THE STUDY REVEALS ABOUT SEDENTARY BEHAVIOR AND HEART DISEASE
The study followed 89,530 participants from the UK Biobank, aged 62 on average, for eight years. The results showed that sedentary time was linked to higher risks. These risks include atrial fibrillation (AF), heart failure, myocardial infarction (MI), and cardiovascular mortality. Exercise reduced the risks of AF and MI for those meeting the recommended activity levels. Still, it did not diminish the impact of prolonged sitting on heart failure. It also did not lessen the risk of cardiovascular death.
THRESHOLD EFFECT: RISK INCREASES AFTER 10.6 HOURS OF SITTING
For heart failure and cardiovascular mortality, the risk remained relatively low until sedentary time exceeded about 10.6 hours a day. After that, a marked increase in risk was observed, indicating a threshold effect for sedentary behavior.
BREAKING THE CYCLE: REDUCING SEDENTARY TIME FOR BETTER HEART HEALTH
Experts suggest that future health guidelines should emphasize reducing sedentary time. “Avoiding more than 10.6 hours per day may be a realistic target for better heart health,” said Dr. Khurshid. Even replacing 30 minutes of sedentary time with physical activity can significantly reduce heart disease risks.
THE IMPACT OF SMALL LIFESTYLE CHANGES
Dr. Charles Eaton, Director of Brown University’s Department of Family Medicine, highlighted the importance of small changes. Replacing just 30 minutes of sitting with any type of physical activity can lower heart health risks. Studies show that even light activity can reduce the risks of heart failure and cardiovascular mortality.
SEDENTARY BEHAVIOR: A GROWING CONCERN FOR HEART HEALTH
Harlan M. Krumholz, MD, editor-in-chief of JACC, stressed the importance of reducing sedentary behavior. “We need to get people moving to promote better health,” he said. This growing body of evidence points to the urgent need for lifestyle changes to prevent cardiovascular disease.
STUDY LIMITATIONS AND AREAS FOR FUTURE RESEARCH
The study has some limitations, including the inability to track the specific contexts in which people are sedentary. Workplace habits, for example, could have different impacts on cardiovascular health. Additionally, accelerometers worn on the wrist may misclassify standing as sedentary behavior, potentially skewing results.
MOVING FORWARD: BETTER DATA AND HEALTH GUIDELINES NEEDED
Researchers suggest that a longer monitoring period and more accurate tools, such as thigh-worn accelerometers, could improve data on sedentary habits. Future guidelines may include more detailed recommendations on managing sedentary time to prevent heart disease.
