Sitting for 10 Hours Straight? Here’s How It Endangers Your Health!

Risk Threshold

Shan Khurshid, a cardiac electrophysiologist at Massachusetts General Hospital, explained: "Most people sit for an average of almost 10 hours per day. That’s why it’s important to better understand how sitting and sedentary behavior overall may impact health and whether these effects can be mitigated by exercise and physical activity."

For this situation, it seems there is a “tipping point” at the 10.6-hour threshold. Khurshid noted that this means avoiding such a high level of sedentary behavior might be crucial for reducing the risk of heart failure and cardiovascular-related deaths.

Khurshid is the lead author of a new study recently published in the Journal of the American College of Cardiology (JACC). It shows that sitting for just over 10.5 hours daily is significantly associated with future heart failure and cardiovascular death, even among individuals who meet the weekly recommendation of 150 minutes of moderate-intensity physical activity (MVPA).

Cardiovascular disease is a major public health concern. From numerous studies, we know that adequate exercise can be a powerful way to reduce the risk of future illnesses. Therefore, guidelines clearly recommend achieving at least 150 minutes of moderate-intensity exercise weekly as an important goal. However, the effects of sedentary behavior on cardiovascular diseases are much less understood. If it can be proven that avoiding excessive inactivity is also essential, it provides another tool to improve public health by adjusting physical behaviors.

The Risks of Inactivity Cannot Be Offset by Exercise

Khurshid and his team also found that for study participants who performed the recommended 150 minutes of moderate-intensity physical activity (MVPA) per week or more, the risks of atrial fibrillation and heart attack associated with inactivity significantly decreased. However, performing the recommended weekly exercise did not reduce the increased risk of heart failure and cardiovascular death associated with a sedentary lifestyle.

Those who are more sedentary also tend to exercise less. Khurshid explained that among individuals who met the guideline-recommended levels of MVPA, the effects of sedentary behavior on atrial fibrillation and myocardial infarction risk were significantly reduced. This indicates that most or all of the additional risk associated with sedentary behavior is due to insufficient “moderate-intensity exercise.”

He added: "But in the context of heart failure and cardiovascular deaths, there remains a strong association with increased risk even among generally sedentary individuals who were active. This suggests that excessive inactivity is linked to a higher risk beyond the effects of insufficient exercise for these two conditions. In other words, sufficient physical activity alone is not enough, and sedentary hours must be seriously reduced."