Overview
- A PLOS Medicine paper published this week found each extra hour of prolonged, uninterrupted sedentary time (defined as bouts of at least 30 minutes) was associated with about a 9–10% higher risk of dying from cancer.
- Researchers used wrist accelerometers worn for seven days by roughly 91,000 U.K. Biobank participants and then tracked health outcomes for about 12 years to link sitting patterns with cancer mortality.
- Modeling in the study estimated that swapping one hour of prolonged sitting for one hour of light activity cut modeled cancer-death risk by about 12% while 30 minutes of moderate activity and five minutes of vigorous activity showed smaller and larger modeled reductions respectively.
- The association appeared even among people who met standard exercise guidelines, prompting experts to warn that isolated workouts may not offset long, uninterrupted sitting and to recommend standing or brief movement every 30–60 minutes.
- Authors and commentators stress that the study is observational, that the sample may be healthier than the general population, and that randomized trials are needed to test whether interrupting sitting actually reduces cancer incidence or deaths.