Short bursts of activity to break up long periods of sitting could significantly lower the risk of dying from cancer, a new study has found.
Sedentary behaviour — any activity involving low energy expenditure while sitting, reclining, or lying for at least 30 minutes — is associated with adverse health outcomes.
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People who spent the most sedentary time at once had a higher risk of cancer mortality, overall cancer incidence, obesity-related cancers and type 2 diabetes-related cancers, according to a study published in the PLOS Medicine journal.
For every additional hour of prolonged sedentary behaviour, the risk of cancer death increased by 10%, researchers found.
The good news is that taking a stroll, doing household tasks, or going for a run reduces that risk.
Replacing one hour of sitting time with light physical activity — such as ironing a shirt, washing dishes or walking — reduced the risk of cancer death by 12%. Cutting sitting time by 30 minutes with moderate exercise — such as mopping or brisk walking — reduced the risk by 8%, while five minutes of vigorous activity — for example, running or playing basketball — lowered it by 22%.
“Our findings suggest that the health effects of sedentary behaviour may depend not only on total sedentary time, but also on whether that time is accumulated in prolonged bouts or interrupted by activity,” the authors said.
They added that previous experimental studies have shown that interrupting prolonged sitting with short bouts of activity can improve metabolic responses compared with staying seated without a break.
“Current health guidelines focus heavily on moderate or vigorous exercise, but our findings show that light movement shouldn't be ignored,” the authors wrote.
High sedentary rates
Sedentary behaviour accounts for around 55% of waking time in both children and adults based on self-reported data, the authors noted.
At the 2018 World Health Assembly, countries agreed to a global target of a 15% reduction in physical inactivity by 2030, compared with 2010.
However, the World Health Organization warns that countries are off-track and millions of adults worldwide do not meet the recommended levels of physical activity.
The WHO warned in 2024 that if the trend continues, levels of inactivity are projected to further rise to 35% by 2030.
Physical inactivity is more common among women globally, at 34% compared with 29% for men. People over 60 are also less active than younger adults, underscoring the importance of promoting physical activity in later life.
