Peaking Physical Activity at Certain Times May Cut Colon Cancer Risk

A new study funded by World Cancer Research Fund has found that activity throughout the day, with peaks in the morning and late afternoon, correlated with an 11% reduced risk of developing colorectal (also known as bowel) cancer, compared with other patterns of exercise studied.

This study used accelerometer data (which measures movement) to analyse daily activity. It used a statistical method that examines all of the data and finds common patterns, and how those patterns might be related to the risk of colorectal cancer.

Researchers from Regensburg University utilised data from the UK Biobank, which had contacted 86,252 randomly selected individuals (56% of them women), asking them to wear accelerometers to track their movement over 1 week and following them for 5 years to monitor the development of colorectal cancer. When studying the data, researchers identified a 2-peak pattern of daily physical activity associated with reduced colorectal cancer risk.

The researchers identified 4 different patterns of physical activity throughout the day:

1. Continuous day-long activity
2. Activity later in the day
3. Early and late-day activity
4. Activity in the middle of the day and during the night

The 3rd pattern, where people were active both in the early and late parts of the day, was associated with an 11% lower risk of colorectal cancer, compared with 6% for day-long activity and no change for middle of the day and the night. Data from activity later in the day only was inconclusive. These findings held true even when considering factors such as smoking, shift work and other variables that could affect a person’s cancer risk.

Impact on sedentary lifestyles

In addition, the researchers found that a day-long activity pattern most effectively reduced colorectal cancer risk among individuals who were more sedentary. This may be because the effect of physical activity becomes more obvious when contrasted with a previously more inactive lifestyle, meaning that those who are fit and healthy are already at a reduced level of cancer risk. These findings show how beneficial physical activity can be, especially in those who are more sedentary.

Dr Helen Croker, Assistant Director of Research and Policy at World Cancer Research Fund, said:

“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. This shows the vital importance of World Cancer Research Fund continuing to support research that expands our knowledge to inform cancer prevention going forwards.”

Prof Michael Leitzmann, Chair of the Department of Epidemiology and Preventive Medicine at the University of Regensburg, Germany, who was the lead investigator in the study, 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.”

Reference: Stein MJ, Baurecht H, Bohmann P, et al. Diurnal timing of physical activity and risk of colorectal cancer in the UK Biobank. BMC Med. 2024;22(1):399. doi: 10.1186/s12916-024-03632-4

This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source. Our press release publishing policy can be accessed here.