Exercising first thing in the morning or late at night may be more effective in preventing cancer, research suggests.
One study found that those who were more active at the beginning or end of the day had lower chances of developing bowel cancer.
Experts say the findings suggest there are peak times of physical activity that could be used to design specific cancer prevention strategies.
Researchers used data from the UK Biobank to evaluate 86,252 people aged 42 to 79, who tracked physical activity using a wrist-worn device known as an accelerometer.
Four patterns of activity stood out; continuous activity throughout the day, activity at the end of the day, activity in the morning and evening, and activity at noon and evening.
During the 5 years of follow-up, 529 people were diagnosed with bowel cancer.
Two daily peaks of activity (around 8 a.m. and 6 p.m.) were “associated with a reduced risk of colorectal cancer, over and above the benefits of general physical activity.”
Those who exercised at that time reduced their chances of doing so by 11 percent, compared to those who exercised similarly during other parts of the day.
Actor James Van Der Beek took to social media on Sunday afternoon to reveal that he has been diagnosed with cancer.
Dame Deborah James, nicknamed ‘bowel babe’, died of bowel cancer in 2022 at the age of 40, after being diagnosed at 35.
Lead researcher Professor Dr Michael Leitzmann, from the University of Regensburg, Germany, said: “Our study highlights that not only is physical activity important in reducing the risk of colorectal cancer, but the timing of peak activity at throughout the day could play a crucial role.
“By identifying specific times (early morning and late in the 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 but impactful way for people to further reduce their cancer risk through the timing of their exercise.”
Bowel cancer is the fourth most common cancer in the UK, and an estimated 44,000 people are diagnosed with the disease each year.
Between the early 1990s and 2018, the number of adults aged 25 to 49 diagnosed with bowel cancer increased by a fifth (22 per cent) in the UK.
Dr Helen Croker, deputy director of research and policy at the World Cancer Research Fund, which funded the study published in BMC Medicine, said it was further evidence that exercise was one of the best forms of prevention.
She said: “Being physically active is one of our recommendations for cancer prevention and we know this reduces the risk of cancer.”
“These exciting new findings offer the possibility of developing more specific recommendations, including physical activity patterns and schedules, to reduce cancer risk.”