Extended periods of sitting raise cancer death risk by 9% per hour

An investigation of 91,292 adults in the UK Biobank, monitored with activity trackers for a week and followed for more than a decade, revealed that each extra hour of continuous sitting raises cancer death risk by 9%. The researchers defined prolonged sitting as bouts of at least 30 minutes with minimal movement. In contrast, breaking up sitting with brief activity was associated with lower cancer incidence and mortality, and replacing one hour of prolonged sitting with light activity cut death risk by 12%.

Led by Frederick Ho of the University of Glasgow, the study was published in PLOS Medicine and funded by the American Cancer Society and the U.S. National Institutes of Health. Authors caution that the cohort may not represent the general population and that causality cannot be confirmed. Nonetheless, the findings suggest that even light movement throughout the day could be a valuable public-health strategy.