A lower risk of heart failure is linked not only to doing more exercise, but also independently to spending less time sitting, concluded US researchers after analyzing 8 years of health data on 84,000 men.
Reporting their findings in the journal Circulation: Heart Failure, Dr. Deborah Rohm Young, a senior scientist at Kaiser Permanente in Pasadena, CA, and colleagues describe how they found even among men who exercised regularly, sitting for long periods increased their risk of heart failure.
Dr. Young says the key finding from their study, the first to look at the link between heart failure risk and time spent sitting, is:
"Be more active and sit less. That's the message here."
Heart failure occurs when the heart is unable to pump enough blood and oxygen to other organs of the body. It does not mean the heart has stopped beating, but it is nevertheless a serious condition.
According to the US Centers for Disease Control and Prevention (CDC), heart failure affects over 5 million people in the US, where it contributes to around 1 in 9 deaths and costs the nation an estimated $32 billion a year.
Long time sitting linked to higher risk of heart failure - regardless of exercise
For their study, Dr. Young and colleagues analyzed data on a racially diverse group of 84,170 men taking part in the California Men's Health Study. The participants were between 45 and 69 years old and did not have heart failure when they enrolled in the study.
Over an average follow-up of nearly 8 years, 3,473 of the participants were diagnosed with heart failure.
To assess levels of physical activity, the researchers used metabolic equivalent of task or METs, a measure of the body's energy use, while sedentary time was measured in hours.
When they analyzed the data, they found:
- Independently of sedentary time, men with the lowest levels of physical activity were 52% more likely to develop heart failure, compared with men with the highest levels of physical activity.
- Regardless of how much they exercised, men who were sedentary for 5 hours or more outside of work were 34% more likely to develop heart failure.
- Men who spent more than 5 hours a day sitting outside of work and exercised the least had double the risk of heart failure, compared with counterparts who sat for less than 2 hours a day and exercised the most.
As the researchers did not include data on women, they cannot say whether these results would apply to them. Also, the men were all members of a comprehensive health plan, so it is not clear whether the findings would apply to uninsured men.
Another limitation of the study is that the data only covered time spent sitting outside of work, so strictly speaking, it cannot be said to apply to overall sedentary activity.
Dr. Young says their findings support the American Heart Association recommendation that adults should do at least 150 minutes a week of moderate intensity aerobic exercise to reduce their risk of heart failure and other cardiovascular diseases.
In June 2013, researchers in Sweden also revealed how just a few extra pounds can raise the risk of heart failure.