Exercise is increasingly recognized as a vital component of cancer care, moving from a fringe recommendation to a central pillar in both prevention and treatment. Experts like Dr. Kerry Courneya highlight that effortful exercise offers significant benefits not only for cancer but also for overall health, impacting the cardiovascular, muscular, and immune systems, thus reducing the risk and improving the management of various chronic diseases.

Exercise for Cancer Prevention

About 40% of cancer diagnoses in the US could potentially be prevented through optimal lifestyle choices. While quitting smoking, maintaining a healthy weight, and moderating alcohol consumption are paramount, exercise stands out as a crucial modifiable factor in reducing cancer risk. Evidence suggests that regular physical activity can lower the risk of several cancers, including colon, breast, endometrial, stomach, and esophageal cancers.

For those with limited time, prioritizing exercise after addressing smoking, obesity, and heavy drinking can provide substantial benefits. The general recommendation is:

• At least 150 minutes of moderate to vigorous intensity aerobic exercise per week


• Up to 300 minutes for greater protection


• Muscular strength training may also contribute to risk reduction

The total amount of exercise seems more critical than how it's spread throughout the week, accommodating even "weekend warriors." Importantly, exercise can lower cancer risk regardless of obesity status, suggesting mechanisms beyond weight management are at play. While genetic predispositions like BRCA gene mutations pose a significant risk, exercise has shown benefits in those with a family history of some cancers. Think of exercise as a crucial form of long–term "insurance" against cancer, especially for non–smokers who maintain a healthy weight.

Exercise as a Powerful Tool During Cancer Treatment

Cancer treatments, including surgery, radiation therapy, chemotherapy, targeted therapies, and immunotherapies, can be extensive and take a significant physical and mental toll. Integrating exercise into cancer treatment can help patients manage side effects, improve treatment tolerance, and potentially enhance survival.

Contrary to past advice of resting, studies consistently show that patients who exercise during treatments experience:

• Less fatigue


• Improved sleep quality


• Reduced anxiety and depression


• Better maintenance of physical function

Notably, exercise, particularly weight training, has been linked to a higher completion rate of chemotherapy with fewer dose reductions or delays, which can lead to better treatment outcomes.

The type and intensity of exercise should be tailored to the individual's ability and the specific treatments they are receiving. While most research has focused on aerobic exercise, resistance training is gaining recognition for its importance in maintaining and building muscle mass, which is critical for cancer patients to prevent wasting and improve prognosis. Combining aerobic and resistance exercise may offer additional benefits. High–intensity interval training has shown promise in activating beneficial biological changes, but moderate intensity exercise is also effective.

Unveiling the Mechanisms: How Exercise Fights Cancer

Exercise exerts its anti–cancer effects through several compelling mechanisms:

• Improves the quality and density of blood vessels in tumors, potentially enhancing the delivery of chemotherapy drugs and increasing tumor oxygenation, making radiation therapy more effective.


• Increases blood flow, creating sheer stress that can damage and kill circulating tumor cells, reducing the likelihood of metastasis.


• Reduces insulin and IGF levels, which can fuel cancer cell growth.


• Exerts anti–inflammatory effects.


• Stimulates the immune system, enhancing the activity of natural killer cells and T–cells that can target and destroy cancer cells – essentially acting as a form of "original immunotherapy."

The Psychological Edge: Exercise for Mental Well–being

Beyond the physical benefits, exercise provides crucial psychological support for cancer patients. It can help individuals regain a sense of control and normalcy amidst the disruption caused by cancer. Exercise has been shown to improve self–confidence and self–esteem, and significantly, it can reduce the fear of cancer progression or recurrence, a major source of anxiety for many survivors. These psychological benefits are so profound that some patients report them as more important than the direct anti–cancer effects.

Looking Ahead: Exercise as a Monotherapy and the Need for More Research

Exciting new research is exploring the potential of exercise as a monotherapy, particularly in low–grade, early–stage cancers under active surveillance, where immediate treatment is not required. Studies in men with prostate cancer on active surveillance have shown that high–intensity interval training can lower PSA levels and slow the growth of prostate cancer cells in vitro.

While the evidence supporting exercise's impact on survival and recurrence is growing, more large–scale randomized controlled trials, similar to drug trials, are needed to provide definitive proof and influence widespread clinical practice and insurance coverage. The American Society of Clinical Oncology (ASCO) now recommends aerobic and resistance exercise for all cancer patients undergoing curative treatment, highlighting the increasing acceptance of exercise as a standard part of care.

Practical Advice and Considerations

For individuals undergoing cancer treatment, even small steps towards physical activity can be beneficial. Starting with realistic and feasible activities like walking and gradually progressing under guidance is key. Activity trackers and mobile apps can help patients stay active at home.

If time is limited, focusing on strength training exercises targeting major muscle groups can be particularly valuable due to the critical role of muscle mass. It's essential to be aware of potential risks, such as exacerbating certain symptoms or the risk of fracture in patients with bone metastasis, and to tailor exercise prescriptions accordingly. Despite some potential harms in specific situations, the overwhelming evidence indicates that the benefits of exercise for cancer patients far outweigh the risks.

Conclusion

The latest research underscores the profound importance of exercise throughout the cancer journey. Whether for prevention, managing treatment side effects, potentially improving treatment outcomes, or enhancing psychological well–being, "don't take cancer lying down" serves as a powerful and evidence–based message for all those affected by this disease.

For more insights, watch this video: The Role of Exercise in Cancer Care