New study warns prolonged sitting could increase cancer mortality risk

A new study has found that sitting continuously for more than 30 minutes at a time may be linked to a higher risk of dying from cancer, with researchers suggesting that even brief movement breaks could help reduce that risk.

The research tracked more than 91,000 participants from the UK Biobank over roughly a decade using wearable activity monitors to assess daily movement and sedentary behaviour.

According to the findings, published in PLOS Medicine, prolonged periods of sitting or lying down while awake were associated with an increased risk of cancer mortality. 

Researchers found that the risk rose with every additional hour of uninterrupted inactivity.

Lead author Dr Frederick said the results highlight the importance of breaking up sedentary time throughout the day.

"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."

He added that while current health recommendations primarily emphasize moderate or vigorous exercise, light movement should not be overlooked.

"Current health guidelines focus heavily on moderate or vigorous exercise, but our findings show that light movement should not be ignored," he said, adding that future clinical trials could help develop more personalised recommendations for reducing prolonged sitting.

The study also found that each additional hour of daily inactivity was associated with a 10% increase in the risk of cancer death.

On the other hand, replacing extended periods of sitting with light physical activity, including everyday tasks such as ironing or household chores, was linked to a 12% lower risk of cancer mortality. 

Researchers also noted that 30 minutes of moderate physical activity, such as brisk walking, was associated with an 8% lower overall mortality risk.

However, the researchers cautioned that the study was observational, meaning it identified an association rather than proving that prolonged sitting directly causes cancer deaths.

They stressed that further research and clinical trials are needed to better understand the relationship, while encouraging people to incorporate regular movement breaks into their daily routines as part of a healthier, more active lifestyle.