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Researchers from the University of California-San Diego found that prolonged sedentary behavior, such as sitting for extended periods, can significantly increase the risk of death, particularly among older women. Most importantly, even regular vigorous exercise does not fully counteract this risk.

Sedentary behavior increases mortality risk

The study conducted by Steve Nguyen, a postdoctoral fellow at UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science, analyzed sitting time and daily activity patterns among 6,489 female participants aged 63 to 99. The research, spanning up to a week, monitored participants’ activity using wearable devices. Over eight years, researchers observed mortality rates among the women.

Data analyzed in this report was collected as part of the Women’s Health Initiative (WHI), a long-term national project initiated in 1991. Led by Andrea LaCroix, a Distinguished Professor at the Herbert Wertheim School of Public Health, the study utilized a newly developed algorithm, CHAP, to investigate the association between total sitting time, length of sedentary activity, and the risk of premature death.

According to Nguyen, sedentary behavior encompasses any inactive posture, such as sitting or reclining, with minimal energy output. Past methodologies for assessing sedentary conduct relied on thresholds to recognize minimal or absent motion. The CHAP algorithm, employing machine-learning technology, has been refined to better differentiate between standing and sitting postures, thereby enhancing its precision.

Exercise cannot offset effects of sedentary behavior

Exercise cannot undo the damage caused by excessive sitting. Research shows that regardless of the amount of physical activity, be it low or high intensity, women who sit for prolonged periods face increased health risks. Sedentary behavior reduces muscle contractions, blood flow, and glucose metabolism, which exercise alone cannot fully counteract.

Prolonged sitting can pose health risks, especially if done for about 11 hours a day. The longer one sits continuously, the higher the associated risk. For instance, sitting for more than 30 minutes at a time is riskier than sitting for only 10 minutes. It’s suggested that individuals stand up at least once an hour or every 20 minutes, even if they don’t need to go anywhere, to mitigate these risks.