Being active in the morning and evening could cut bowel cancer risk, study finds

Being more active in the morning and evening could cut the risk of bowel cancer by 11%, according to a study.

Researchers suggest that highlighting specific times when physical activity is “most beneficial” could pave the way for targeted cancer prevention strategies.

The study, led by experts from Regensburg University, used data from the UK Biobank to assess 86,252 people aged 42 to 79, who tracked physical activity by wearing a device on their wrist known as an accelerometer.

Some 529 cases of bowel cancer occurred over a follow-up period of 5.3 years.

Researchers highlighted four activity patterns; continuous day-long activity, activity late in the day, activity in the morning and evening, and activity at midday and at night.

They found two daily peaks in activity, at around 8am and 6pm, “was associated with reduced colorectal cancer risk, beyond the benefits of overall physical activity”.

Bowel cancer – also known as colorectal cancer – can develop anywhere in the large bowel, which includes the colon and rectum.

It is the fourth most common cancer in the UK, with an estimated 44,000 people each year – or about 120 a day – diagnosed with the disease.

Professor Dr Michael Leitzmann, chairman of the department of epidemiology and preventive medicine at the University of Regensburg in Germany, was the lead investigator for the study, published in BMC Medicine.

He said: “Our study highlights that not only is physical activity important for reducing colorectal cancer risk, but the timing of peak activity throughout the day could play a crucial role.

“By identifying specific times – early morning and late day – when physical activity is most beneficial, our findings open new avenues for targeted prevention strategies.

“If confirmed by future research, this could provide a simple yet impactful way for individuals to further reduce their cancer risk through the timing of their exercise.”

Dr Helen Croker, assistant director of research and policy at the World Cancer Research Fund, which funded the study, added: “Being physically active is one of our cancer prevention recommendations, and we know that this cuts cancer risk.

“These intriguing new findings offer potential for developing more specific recommendations, including patterns and timing of physical activity, for reducing cancer risk.”