Prolonged sitting interrupted by light activity may play a role in reducing cancer risk
CANCER DIGEST – Sept. 20, 2026 – Uninterrupted sitting for prolonged periods of time can boost the risk of dying of cancer by 9 percent according to a new study published in the journal PLOS, the peer reviewed journal of the Public Library of Science.
The July 1, 2026 study was led by Frederick Ho of the University of Glasgow, UK, and involved over 91,000 participants who wore an accelerometer, a device that measures movement, for seven days, and were then followed for a median of 12 years.
The researchers divided the participants into categories based on activity levels. People who sat for at least 30 minutes at a time with 90 percent of the time spent sitting were categorized as a prolonged sedentary group. People who sat less than 30 minutes at a time or who spent 10 percent of their time in non-sedentary activity were categorized as interrupted sedentary group.
After 12 years of analysis the researchers found that those in the prolonged sedentary group had an 11 percent higher incidence of obesity-related cancers, such as esophageal, liver, kidney, pancreatic, colorectal, breast, ovarian, and thyroid, and type-2 diabetes related cancers and a 12 percent higher risk of dying from cancer as compared to the population.
The same analysis of the interrupted sedentary group, however, showed the risk of dying of cancer was 12 percent lower compared to the prolonged sedentary group.
"Our findings suggest that the health effects of sedentary behavior may depend not only on total sedentary time, but also on whether that time is accumulated in prolonged bouts or interrupted by activity," the authors wrote. "This pattern is biologically plausible: experimental studies have shown that interrupting prolonged sitting with short bouts of activity can improve metabolic responses compared with uninterrupted sitting."
The findings point to a beneficial effects of breaking up prolonged sitting with everyday activity, as opposed to moderate or vigorous exercise. Such non-exercise activity can play a role in moderating the health effects of sedentary behavior.
"Current health guidelines focus heavily on moderate or vigorous exercise," the authors wrote, "but our findings show that light movement shouldn't be ignored. Moving forward, clinical trials will help us move beyond blanket advice and develop personalized strategies for breaking up sitting time."
The study was funded by the American Cancer Society and the National Institutes of Health.
Source: ScienceDaily, 2 September 2026
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