Being more active in the morning and evening may reduce the risk of bowel cancer by 11%, according to a study that suggests the timing of peak activity could play a crucial role in warding off the disease.
Researchers said that highlighting specific times when physical activity was “most beneficial” could pave the way for targeted cancer prevention strategies, reports The Guardian.
The study, led by experts from the University of Regensburg in Germany, used data from the UK Biobank to assess 86 252 people aged 42 to 79, who tracked their physical activity by wearing a wrist accelerometer device.
Some 529 cases of bowel cancer occurred over a follow-up period of more than five years, and researchers highlighted four activity patterns: continuous daylong 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 about 8am and 6pm, “associated with reduced colorectal cancer risk, beyond the benefits of overall physical activity”.
People active in both the early and late parts of the day had an 11% lower risk of colorectal cancer, compared with 6% for daylong activity and no change for middle of the day and the night. Data from those who were active later in the day only were inconclusive, according to the research, published in BMC Medicine.
The findings held true even when considering factors like smoking, shift work and other variables that could affect a person’s cancer risk, the study found.
Professor Dr Michael Leitzmann, chair of the Department of Epidemiology and Preventive Medicine at Regensburg, and lead investigator for the study, said: “Our findings highlight that not only is physical activity important for reducing colorectal cancer risk, but the timing of peak activity 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.”
Bowel – or colorectal – cancer can develop anywhere in the large bowel, which includes the colon and rectum, and is one of the most common cancers worldwide.
Study details
Diurnal timing of physical activity and risk of colorectal cancer in the UK Biobank
Michael J. Stein, Hansjörg Baurecht, Patricia Bohmann, Béatrice Fervers, Emma Fontvieille, Heinz Freisling, Christine M. Friedenreich, Julian Konzok, Laia Peruchet-Noray, Anja M. Sedlmeier, Michael F. Leitzmann & Andrea Weber.
Published in BMC Medicine on 24 September 2024
Abstract
Background
Physical activity reduces colorectal cancer risk, yet the diurnal timing of physical activity in colorectal cancer etiology remains unclear.
Methods
This study used 24-h accelerometry time series from UK Biobank participants aged 42 to 79 years to derive circadian physical activity patterns using functional principal component analysis. Multivariable Cox proportional hazard models were used to examine associations with colorectal cancer risk.
Results
Among 86,252 participants (56% women), 529 colorectal cancer cases occurred during a median 5.3-year follow-up. We identified four physical activity patterns that explained almost 100% of the data variability during the day. A pattern of continuous day-long activity was inversely associated with colorectal cancer risk (hazard ratio (HR) = 0.94, 95% confidence interval (CI) = 0.89–0.99). A second pattern of late-day activity was suggestively inversely related to risk (HR = 0.93, 95% CI = 0.85–1.02). A third pattern of early- plus late-day activity was associated with decreased risk (HR = 0.89, 95% CI = 0.80–0.99). A fourth pattern of mid-day plus night-time activity showed no relation (HR = 1.02, 95% CI = 0.88–1.19). Our results were consistent across various sensitivity analyses, including the restriction to never smokers, the exclusion of the first 2 years of follow-up, and the adjustment for shift work.
Conclusions
A pattern of early- plus late-day activity is related to reduced colorectal cancer risk, beyond the benefits of overall activity. Further research is needed to confirm the role of activity timing in colorectal cancer prevention.
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