- Living a sedentary lifestyle can harm your overall health, and sitting too much each day can particularly be harmful to your heart.
- A new study suggests that sitting for 10.6 hours or more a day is significantly linked to future heart failure and cardiovascular death risk.
- This risk is still heightened in people who meet the recommended 150 minutes of moderate to vigorous exercise per week.
“Most people spend much of the day, an average of roughly 10 hours, sitting,” Shaan Khurshid, MD, MPH, cardiac electrophysiologist at Massachusetts General Hospital told Medical News Today. “For this reason it’s important to better understand how sitting and sedentary behavior in general may affect health, and whether these effects may be mitigated by exercise and physical activity.”
Khurshid is the co-senior author of a new study recently published in JACC, the flagship journal of the American College of Cardiology, which found that sitting for a little more than 10-and-a-half hours a day may be significantly linked with future heart failure and cardiovascular death, even among people who meet the recommended
“Cardiovascular disease is a major public health problem, and we know from many studies that getting enough exercise can be a powerful method of reducing risk of future conditions. For this reason, the guidelines are clear that achieving at least 150 minutes per week of MVPA is an important goal,” Khurshid said.
“By contrast, the effects of sedentary behavior on cardiovascular disease are much less understood. Yet, if it can be better established that avoiding excess sedentary behavior is also important, it provides another means by which we can potentially improve public health by modifying movement behaviors,” he continued.
All participants had worn a triaxial accelerometer on their wrists for more than seven days to measure their movement.
After a follow-up of a median of eight years, about 5% of study participants developed atrial fibrillation, about 2.1% developed heart failure, almost 2% had a heart attack, and a little less than 1% died from cardiovascular-related causes.
Upon analysis, scientists found that risks for atrial fibrillation and heart attack — clinically known as myocardial infarction — steadily increased over time.
However, the risk increase was minimal for those who experienced heart failure or cardiovascular-related death until their sedentary time went over about 10.6 hours each day. At that point, researchers report that their risk rose significantly.
“For these conditions, there appeared to be an ‘inflection point’ of risk at this 10.6-hour threshold. That means that getting as many people as possible to avoid this level of sedentary behavior may be particularly important for risk of heart failure and cardiovascular mortality,” Khurshid explained.
Khurshid and his team also discovered that for study participants who met the recommended 150 minutes a week of MVPA or more, their sedentary behavior-related atrial fibrillation and heart attack risks were substantially reduced.
However, meeting the recommended weekly exercise did not lower sedentary lifestyle-related increased risk for heart failure and cardiovascular death.
“People who are more sedentary also tend to engage in less exercise or MVPA. Among people who met guideline-recommended levels of MVPA, effects of sedentary behavior on atrial fibrillation and myocardial infarction risks were substantially reduced, suggesting that much or all of the excess risk associated with sedentary behavior is related to insufficient MVPA,” Khurshid explained.
“But for heart failure and cardiovascular mortality, strong associations with increased risk persisted even among individuals who were active, suggesting that excess sedentary behavior is associated with greater risk above and beyond the effects of insufficient activity for those two conditions,” he added.
For the thousands of us who have sitting jobs where we’re behind a desk all day, Khurshid said their study does suggest that avoiding excess sedentary behavior remains important even among people who get enough exercise.
“Our advice would be to try to work in ways to avoid too much sitting into the day, such as fitting in walking time or trying to incorporate some standing into the day — e.g., using a standing desk if that is an option. We also saw that the effects of excess sitting did appear somewhat ‘dose-dependent’, where lowering the number of days of the week above the 10.6-hour threshold was also important. So even if they cannot avoid excess sedentary time on all days, even reducing it on some days is still potentially helpful.”
— Shaan Khurshid, MD, MPH
“We measured physical activity for one week, which is customary in studies using activity trackers. We plan to follow up our findings using longer durations of monitoring. There is reason to believe that sedentary behavior may affect disease risk far beyond cardiovascular disease, so we also plan to investigate associations across the full spectrum of health,” Khurshid added.
MNT also spoke with Christopher Berg, MD, a board certified cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, about this study.
“While I’m not that surprised (by) the findings of the study, it is really important that this study was done. The medical literature has been clear that low level of activity and sedentary behavior is adversely associated with metabolic and cardiovascular health. However, there may have been a sentiment or a belief that a sedentary lifestyle can be counteracted with performing the guideline recommended amounts of exercise,” Berg said.
“Unfortunately, this appears to be only partly true. Exercising the guidelines recommended amount cannot completely undo a sedentary lifestyle. A silver lining was provided by the authors. However, they note that reallocation of sedentary minutes to either light activity or exercise can decrease the risk of cardiovascular disease. That said whether you can completely negate a sedentary lifestyle was not determined,” he continued.
From this data and much of research that has come before this study, Berg said there is no doubt that readers with a sitting job would have less risk of cardiovascular disease if they did not.
“However, there is good news that risk reduction can be accomplished by substituting sedentary minutes for active minutes. Do not rob yourself of the opportunity to take a flight of stairs or park farther away to get in a few more steps — the findings from this study suggest that even small steps (literally) can make a cumulative difference toward reducing cardiovascular risk.”
— Christopher Berg, MD
“If you wear a smartwatch, utilize the function where it sends a ‘move’ reminder if it detects that you haven’t moved or taken enough steps in the previous hour. As mentioned previously, finding or scheduling movement breaks in the workday can be really helpful. Also popular is the idea of ‘activity snacks,’ which are short (30 seconds to 5 minutes) bursts of activity to get the heart rate up. Examples would be jogging up a flight of stairs or doing a quick set of burpees or push-ups,” Berg added.
