Extra hours of unbroken sitting linked to higher cancer death risk, study finds

A prolonged sedentary lifestyle, particularly unbroken periods of sitting, poses a significantly higher risk of cancer-related death than overall daily inactivity. New research published in the journal PLOS Medicine indicates that each additional hour spent sitting continuously raises this mortality risk by 9 percent. Unpacking Sedentary Behavior A research team from the University of Glasgow, led by Frederick Ho, examined health data from 91,292 volunteers enrolled in the UK Biobank. Participants wore activity-monitoring devices for a week. Researchers then tracked these individuals for an average of nearly 12.4 years, categorizing their sedentary behavior into two distinct types: Prolonged Sedentary Periods: These were defined as intervals of at least 30 minutes where individuals remained largely stationary, engaging in activity for no more than 10% of the time. Intermittent Sedentary Periods: This category encompassed shorter sitting sessions (under 30 minutes) or instances where activity constituted more than 10% of the duration. Findings: The Peril of Unbroken Sitting The study's results revealed a strong correlation between prolonged sitting and increased cancer mortality. This extended inactivity was also linked to a higher overall cancer incidence and a greater risk of developing type 2 diabetes. Notably, the researchers found associations with cancers commonly linked to obesity, including those affecting the bowel, liver, kidneys, pancreas, esophagus, breast, ovaries, and thyroid.

Sitting for long, uninterrupted stretches may carry greater health risks than sitting the same amount of time in shorter bouts. Researchers found that each extra hour of prolonged sedentary behavior was associated with a 9% higher risk of cancer death. Breaking up sitting with movement showed the opposite pattern, while replacing an hour of prolonged sitting with light activity was linked to a 12% lower risk.