June 20, 2022 – You probably know that sitting for hours on end is not good for you. New research now shows just how bad it can be.
In a study that tracked more than 100,000 adults from 21 countries for more than 10 years, more time spent sitting during the day was tied to a higher risk of early death and heart disease.
The combination of prolonged sitting and physical inactivity was particularly harmful – nearly as bad as smoking.
But the good news is that boosting physical activity appeared to reduce the risks of prolonged sitting, the researchers found.
"If you must sit, getting in more exercise at other times during the day can help offset the risks," says study investigator Scott Lear, PhD, a professor at Simon Fraser University in Vancouver.
"Humans seem built to move – and to suffer if we do not," says Harlan Krumholz, MD, with Yale School of Medicine, who wasn't involved in the study.
The study showed that sitting for 8 or more hours per day was linked to a roughly 20% higher risk of getting heart disease or dying from any cause over the study period, compared to those who sat for only half that time. The prolonged sitters were also 49% more likely to have heart failure.
Even sitting for 6 to 8 hours daily was associated with a 12% higher risk of early death and a 13% higher risk of heart disease.
This was true for people living in high-income, middle-income, and low-income countries.
The health benefits of being physically active were also clear in the study. People who sat the most and were the least active had the highest risk (up to 50% greater risks), but for people who sat the most and were active, the risk was only 17%.
Finally, those who both sat the least and were the most active had the lowest risk of early death and heart disease.
Krumholz says the link between sitting and premature death and heart disease is "plausible, and the solution – more physical activity – has little downside and much upside."
"As our society increasingly drifts toward more screen time and less physical activity, we need to consider what effects that might have on our long-term health and function," he says.