Sitting for longer than half an hour at a stretch each day raises the risk of dying from cancer, according to a study that tracked more than 90,000 people over a decade. Researchers at the University of Glasgow found that every additional hour of continuous inactivity was associated with a 10% increase in the risk of cancer death.
The study, published in Plos Medicine, analysed data from wearable devices worn by more than 91,000 UK Biobank participants, who were followed for an average of 12 years. It found that sitting or lying down while awake for more than 30 minutes in one period each day was associated with an increased risk of cancer death — and the risk grew with each extra hour of prolonged sedentary behaviour.
“Prolonged sitting of over 30 minutes daily linked to increased cancer death risk; breaks with light activity reduce risk.”
But the researchers also found that breaking up long periods of inactivity with bursts of physical activity could help reduce the risk. Dr Frederick Ho, the lead author, 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.”
Beneficial activities included slow walking, housework and even light tasks such as ironing. “Current health guidelines focus heavily on moderate or vigorous exercise, but our findings show that light movement should not be ignored,” Ho said. “Moving forward, clinical trials will help us move beyond blanket advice and develop personalised strategies for breaking up sitting time.”
The findings add to growing evidence linking prolonged sedentary behaviour to cardiovascular disease and some cancers. While long periods of sitting have long been associated with such risks, the researchers say less is known about how the way sedentary time is accumulated influences health. This study suggests that getting up every half-hour, even for a short walk around the office, could do wonders for health.