Bad news for the desk-bound office worker, the long-haul road warrior, and the couch surfer: Even a heart-pumping regimen at the gym, apparently, won't undo the harm done by sitting, a new study finds.

Irrespective of time spent in moderate to intensive physical activity, says the research, those who do the most sitting have the highest levels of calcification in arteries feeding blood to their hearts.

Coronary artery calcification leads to the formation of sticky plaques inside arteries. The plaque narrows the vessels and can break off, causing heart attacks. The new study, to be presented at a meeting of the American College of Cardiology, found that levels of this early biomarker for heart disease correlated with hours of daily sitting by 2,031 participants.

For each daily hour of sedentary time, average coronary artery calcification levels increased by 14 percent.

On average, participants spent 5.1 hours sitting daily. The average amount of time spent in daily exercise was only six minutes, said Jacquelyn Kulinski, a cardiologist at the Medical University of Wisconsin, and the study's lead author.

Recent studies have linked excess sitting with higher rates of diabetes, cardiovascular disease, cancer, and early death. This latest research bolsters previous evidence that punctuating sedentary behavior with exercise does not undo the harm of sitting for lengthy periods.

"It's clear that exercising is important to reduce your cardiovascular risk and improve your fitness level," Kulinski said. "But this study would suggest that reducing how much you sit every day may represent a more novel, companion strategy [in addition to exercise] to help reduce your cardiovascular risk."

Kulinski added that future research should focus on how fewer hours of sitting can improve health.
- Los Angeles Times