Prolonged sedentary time is associated with an increased risk of heart disease, particularly heart failure and cardiovascular-related death, a new study has warned.
The study by researchers at Mass General Brigham highlights that simply fitting in a workout after a long day of sitting may not be enough to counteract the harmful effects of sedentary behavior on heart health. It defines sedentary behavior as waking activities with low energy expenditure, such as sitting, reclining, or lying down, excluding sleep.
The findings showed a sedentary lifestyle may raise the risk of the most common heart diseases, even in individuals who meet recommended exercise guidelines. However, replacing sedentary time with other activities significantly reduces these risks.
The study, published in the Journal of the American College of Cardiology, also found that meeting recommended levels of moderate-to-vigorous physical activity alone may not be sufficient to lower cardiovascular risk if excessive sitting remains a part of daily life. These
“Many of us spend the majority of our waking day sitting, and while there’s a lot of research supporting the importance of physical activity, we knew relatively little about the potential consequences of sitting too much beyond a vague awareness that it might be harmful,” said lead author Ezimamaka Ajufo, a cardiology fellow at Brigham and Women’s Hospital.
“Sedentary risk remained even in people who were physically active, which is important because many of us sit a lot and think that if we can get out at the end of the day and do some exercise we can counterbalance it. However, we found it to be more complex than that,” Ajufo said.
Study Findings and Health Risks
The team analyzed one week of activity-tracker data from 89,530 individuals from the UK Biobank prospective cohort. They looked at associations between daily time spent sitting and the future risk of four common cardiovascular diseases: atrial fibrillation, heart attacks, heart failure, and death from cardiovascular causes. The team used a machine learning algorithm to classify sedentary behavior.
The researchers found sedentary behavior was associated with higher risks of all four types of heart disease, with a marked 40-60 percent greater risk of heart failure and cardiovascular death observed when sedentary behavior exceeded 10.6 hours a day (not including hours spent sleeping).
Many of the negative effects of sedentary behavior persisted even among those individuals who achieved the guideline-recommended >150 minutes of moderate-to-vigorous physical activity per week. For example, although the study found that the risk of atrial fibrillation and heart attacks could be mostly eliminated by engaging in physical activity, the excess risk of heart failure and cardiovascular death could only be partially offset by physical activity.
Importance of Reducing Sedentary Time
“Our data supports the idea that it is always better to sit less and move more to reduce heart disease risk, and that avoiding excessive sitting is especially important for lowering the risk of heart failure and cardiovascular death,” said co-senior author Shaan Khurshid, an electrophysiologist and faculty member in the Telemachus And Irene Demoulas Family Foundation Center for Cardiac Arrhythmias at Massachusetts General Hospital.
The research team hopes these findings will help inform future guidelines and public health efforts. They would like future prospective studies to test the efficacy of public health interventions that help people reduce the number of hours they spend being sedentary and see how that affects cardiovascular health.