The complex Relationship Between Endurance Exercise and Bowel Cancer: A Cautious Examination
Recent research has sparked debate regarding a potential link between high levels of endurance exercise and an increased risk of advanced adenomas – precursors to bowel cancer. A study examining long-distance runners revealed that 15% had advanced adenomas, a figure some experts consider surprisingly high. However,the findings are being met with caution within the medical community due to a meaningful limitation: the study lacked a control group of individuals aged 35-50 who do not engage in regular running,making direct comparison unachievable.
This absence of a control group prevents researchers from definitively concluding whether the observed rate indicates a genuine increased risk associated with extreme endurance sport, or if it’s simply a statistical anomaly. experts emphasize that, at present, there is no reason for individuals to discontinue exercise or reduce their fitness levels.
Further investigation is underway to explore potential contributing factors, including dietary habits and specific training regimens, that might explain the unexpected results. These findings stand in contrast to a considerable body of existing research demonstrating the protective effects of exercise against various cancers. Cancer Research UK, for example, states that being physically active can lower the risk of 13 different cancer types.
Indeed,current recommendations advocate for at least two hours of exercise per week to reduce the risk of bowel cancer,as highlighted by Dr. Kevin Monahan, a consultant gastroenterologist at St Mark’s Hospital in London. Many medical professionals, including Dr. Monahan himself, actively incorporate exercise into their daily routines, citing the overwhelming evidence of its cardiovascular benefits.
Professor Trevor Graham, director of the Center for Evolution and Cancer at the Institute of Cancer Research in London, reinforces this point, stating that exercise is “extremely well established to be protective against cancer,” notably when initiated during youth. Moreover, exercise demonstrably improves outcomes for those undergoing cancer treatment. A recent study published in the New England Journal of Medicine found that colon cancer patients participating in a structured exercise program - including a daily 40-minute brisk walk – experienced a 37% reduction in mortality risk over eight years compared to those simply provided with exercise information.
The story of Alison, a long-time runner who ran the London Marathon in both 2006 and 2023 (the latter to raise funds for Bowel Cancer UK), illustrates the complexities of this issue. her colon cancer was discovered incidentally while she increased her marathon training, prompted by a change in bowel habits she mentioned to her doctor during a routine appointment. Following diagnosis in June 2023, Alison underwent surgery and chemotherapy, and has as returned to running, even completing a 10km race.
Alison herself believes running played a role in her early diagnosis, stating her symptoms were so mild she likely wouldn’t have sought medical attention or else. Despite the recent study, she remains committed to continuing her running routine.
The current consensus remains that the benefits of exercise overwhelmingly outweigh any potential, and as yet unproven, risks. Ongoing research is crucial to fully understand the relationship between endurance exercise and bowel cancer, and to provide more definitive guidance.
