A new study from the University of Glasgow has found that spending more than 30 minutes continuously sitting each day could raise the risk of dying from cancer. The research, published in PLOS Medicine, analyzed data from over 91,000 UK Biobank participants who wore wearable devices and were followed for an average of 12 years.
Key Findings on Sedentary Behaviour and Cancer Risk
The study identified a clear link between periods of sitting or reclining for over half an hour at a time and an increased likelihood of cancer mortality. Each additional hour of prolonged inactivity every day was associated with a 10% higher risk of cancer death. The risk escalated with every extra hour of uninterrupted sedentary behaviour.
Dr Frederick Ho, lead author of the study, said: “What our data shows is that sitting for more than 30 minutes at a time is particularly linked to a higher risk of cancer. The good news is that breaking up your sitting time with something as simple as a short walk could be protective.”
Physical Activity as a Mitigating Factor
The researchers found that replacing sedentary habits with physical activity could reduce cancer risk by more than 20%. Specifically, replacing one hour of sedentary behaviour with light physical activity each day—such as slow walking or routine housework like ironing or dishwashing—was associated with a 12% lower risk of cancer death. Replacing 30 minutes of inactivity with moderate physical activity (e.g., walking at an average pace) lowered the risk by 8%, while replacing five minutes with vigorous activity reduced the risk by 22%.
Implications for Health Guidelines
Dr Ho added: “Current health guidelines focus heavily on moderate or vigorous exercise, but our findings show that light movement shouldn’t be ignored. Moving forward, clinical trials will help us move beyond blanket advice and develop personalised strategies for breaking up sitting time.”
The study, titled "Accelerometry-measured prolonged and interrupted sedentary behaviour and cancer incidence and mortality: A cohort study of 91,292 UK Biobank participants," highlights the importance of breaking up long periods of sitting with even light activity to reduce cancer risks.
