Exercising and a good diet may not be enough to prevent you from getting cancer in the first place. But once you get it, it puts you in a much better position to heal than if you are overweight, unfit and eating poorly. Without a foundation of good health, the body cannot cope with the added stress of aggressive disease. There just aren’t enough resources to go around. Once you get the condition, you must keep exercising and eating well.
The first time around, I didn’t pay enough attention to this. The second time around, I ensured I got at least 30 minutes of exercise today, even during the bad days of chemotherapy. On my worst days, I would break the thirty minutes down into 10 minutes sessions three times a day.
The other exercise I did was a 10-minute session of Qi Gong after my morning meditation. It helps keep the body flexible and the life force moving. I would practice Qi Gong under a tree during the summer to absorb the Qi. I also did some easy weight training with dumbbells.
Cancer and exercise – the science
Research shows that exercise can lower cancer risk and improve treatment outcomes. In this post, I look at the science behind the risks of not exercising and the benefits of exercising during treatment.
Exercising alone may not prevent you from contracting cancer. But a fit body will improve your chance of surviving once diagnosed. Being active during treatment will also improve your outcome.
I’ve been physically active all my life. I was a mountaineer and ski patroller in my twenties and fifties and ran ultra marathons. This alone did not prevent me from getting cancer but once diagnosed, it improved my outcome and helped during treatment.
Physical activity and cancer risk
Scientific studies show that increased physical activity is associated with a decrease in the development of many types of cancer. Studies show that being overweight, physically inactive and poor diet increases your cancer risk.
Inactivity is associated with a higher risk of developing cancer. Inactivity is responsible for 14% of colon and 11% of breast cancers. It contributes to many other cancers, including bowel, prostate, uterine and lung cancer. Being overweight also increases cancer risk.
Physical activity regulates hormones and reduces exposure to dietary carcinogens by speeding up food passing through the bowel. Activity can also reduce stress, another contributor to cancer and poor treatment outcomes.
Mechanisms that link activity to cancer risk include a decrease in inflammation, insulin-like growth factor, sex hormones, leptin and other obesity-related metabolites.
Being physically active can help prevent cancer from coming back. Physical activity can reduce insulin growth factors, which promote the growth of cancer cells.
But how much activity do you need? The more exercise you do, the lower your cancer risk. At the minimum, you need to be physically active for at least 150 minutes per week1
This equates to 30 minutes of moderate physical activity daily. Three 10 minutes sessions are also good. To reduce your cancer risk further, the more physically active you are, the better.
Moderate physical activity is any activity in which you can still hold a conversation, including brisk walking and jogging. Household activities like hanging up the washing, cleaning windows, raking leaves, or mowing count as moderate activities.
High-intensity physical activity is any activity that makes you ‘huff and puff’, such as fast swimming, cycling or running.
Tips for getting moving
- Break up long periods of screen time every 25 minutes
- Walk or cycle to the local shops
- Do gardening or housework
- Walk your children to school
- Catch public transport to work
- Get off a stop earlier
- Park your car 15 minutes from work
- Walk at lunchtime
- Take the stairs
Exercise and the microbiome connection
A healthy gut microbiome is not only helpful in lowering cancer risk. It is also crucial for a positive response to treatment.
There’s a whole world living inside your large intestine. This ecosystem includes bacteria that perform various essential digestive and overall health functions. It eats what you eat, and it gets stressed when you eat. Exercise and physical activity enhance your GM’s diversity and function.
Interestingly, there is a link between the gut microbiome and exercise. Studies suggest that exercise benefits the gut microbiome. Exercise increases the number of beneficial bacteria and diversity. It also enhances the short-chain fatty acid synthesis and carbohydrate metabolism.
Studies show that even little changes can yield results. One study investigated the microbiomes of professional international rugby union players compared to control groups. It found a higher diversity among the athletes. Studies indicate that aerobic exercise benefits your microbiota in terms of increased abundance of beneficial bacteria and overall diversity.
A study in the National Library of Medicine shows that physical activity improves immune function and the diversity of the gastrointestinal microbiome. Moderate physical activity is essential for cancer protection. The most significant inflammatory profile changes are from high-intensity physical activity.
In addition, regular aerobic activity reduces the transient stool time and contact time between pathogens and the gut lining. Other positive effects of exercise include:
- Elevated short-chain fatty acids (SCFAs)
- Immunoglobulin production
- An increase in butyrate concentration
Butyrate encourages the repair of the gut lining and reduces inflammation, leading to disease. Aerobic exercise alters the gut microbiome without changing dietary patterns. The evidence supports the notion that physical activity is an essential factor that induces changes in microbial composition and stimulates gut bacteria to protect against cancer.2
The following figure from Frontiers in Nutrition clearly illustrates the relationship between the gut microbiome and exercise. The figure shows a decrease in pathobionts or the “bad guys” and increased diversity as activity increases.
Source: https://www.frontiersin.org/articles/10.3389/fnut.2021.637010/full
The study concluded that changes in the gut microbiota diversity and composition could reduce inflammation and gastrointestinal symptoms. Probiotics benefit the GM further. The research needed to identify the best bacterial strains and administration methods.
One study found that three hours of light exercise per week increased levels of beneficial bacteria compared with sedentary individuals.
Studies have also examined the link between exercise and the gut microbiome in cancer survivors. A trial in Alabama looked at whether home exercise regimens impacted the human gut microbiome by recruiting breast cancer survivors.3
An MDPI Open Access Journal study examined the relationship between exercise and prebiotic fibre in cancer survivors. The GM influences patient response to several cancer therapies. At the same time, chemotherapy can disrupt the gut microbiota and contribute to poor health outcomes.
Strategies to improve the composition of the gut microbiota include diet and exercise. Their findings indicated that exercise and prebiotic fibre supplementation might benefit individuals through gut microbial changes. The study concluded that the results point to exercise and prebiotic supplementation in cancer treatments.4
The link certainly rings true for me. By adopting a more plant-based diet rich in fibre from the Mederterannean diet and supplementing with resistant starch and increased exercise, my experience with chemotherapy and outcomes were far more positive than my first experience.
The guidelines for exercising to help the GM are similar to those recommended for cancer prevention and treatment: a minimum of 150 minutes of moderate aerobic activity every week and strength exercises on two or more days a week.5
Physical activity and different types of cancer and survival
Another study published in the National Library of Medicine found strong evidence that physical activity reduces the risk of breast, colon, uterine, stomach, esophagus and kidney cancers. Of interest to me was the evidence that exercise reduced the risk of bladder cancer as well.
There was moderate evidence for a link with lung cancer risk, with limited evidence for prostate cancer. Research showed little evidence for blood, head and neck, ovary, and pancreas cancers. There is insufficient evidence for a link between physical activity for brain cancer and other cancer sites.
Early results of the study indicated a 40-50% risk reduction in mortality for breast, colon and prostate cancers with increased levels of physical activity.6
Inactivity and Cancer Risk
A study published in the Journal of the National Cancer Institute provides evidence that despite regular exercise, inactivity may play a role in cancer risk.
This is an important point, it’s not enough to be physically active for 30 – 60 minutes a day, but you have to reduce the time you are sitting around. It is, therefore, essential to move throughout the day and not just exercise.
The study investigated sedentary behaviour and cancer incidence by looking at TV viewing time, recreational sitting and occupational sitting. Research suggests the effect was independent of how active participants were, indicating that sedentary behaviour represents a cancer risk factor distinct from physical inactivity.
Sedentary behaviour increases the risk for colon, uterine, and lung cancer. For every two hours of sitting, the risk increased by 8 per cent for colon cancer and 10 per cent for uterine cancer. Long periods of watching TV showed the strongest relationship with increased risk of colon and uterine cancers.7
Exercise during treatment
Research shows that exercise has benefits during and after cancer treatment. The evidence also shows little risk from exercise when performed under professional supervision. For some cancers, exercise may even improve treatment outcomes.8
I could barely walk around the block when I first got out of the hospital in 2019. I gradually increased my endurance. On my bad days during chemo, I could barely lie on the couch but I still got out walking. On the off weeks, I introduced renaissance stretching, supervised by a physio.
Between my two diagnoses, I continued to walk and introduced weight training to regain my fitness.
After my second diagnosis and during chemo, I continued to exercise. There were very few days I did not feel like exercising. I walked first thing in the morning during summer. This had the added benefit of optimising melatonin with early morning light.
I also introduced Qi Gong, which I practised outside after mediation every morning. Exercise felt more beneficial the second time around. I would listen to upbeat music as well.
Exercise helped with the side effects and my overall recovery and well-being, both mentally and physically. I would often break the walking sessions down into 10-15 minutes three times a day if I felt fatigued.
Some days were more challenging, but even a few minutes of light exercise felt better than no exercise. I had two exercise plans – one for good days and another for bad days.
The following are the benefits of exercise during cancer treatment:
- Improve how treatment works and reduce treatment side effects
- Improve overall health status
- Reduce risks of coexisting conditions and other cancers
Exercise is associated with better survival rates for certain cancers, including breast and colorectal cancer.9
Recommended exercises include:
- Stretching – helps increase blood and oxygen flow to the muscles and can help your body repair itself. Stretching can help break down stiff scar tissue and restore range of motion after surgery. The warm-up exercises for QI Gong include stretching
- Balance – loss of balance can be a side effect of cancer and its treatment. Qi Gong warm-up exercises include balance routines
- Aerobic – strengthening the body’s heart and lungs can help you feel less tired during and after treatment. I walk 30-60 minutes daily 3-4 times a day at a moderate pace.
- Strength training – muscle loss often happens when a person is less active during cancer treatment and recovery. You can use resistance bands or weights. I prefer dumbbells. Strength training twice a week is recommended by the CDC.10
Conclusion
There is no doubt about that there is a heightened cancer risk factor from inactivity. Conversely, there are benefits from exercising during treatment and preventing recurrence. Interestingly there is emerging evidence that there is also a direct relationship between the health and diversity of the gut microbiome, exercise and cancer. The simple message is whatever you do – get moving for your health’s sake.
References
- Move your body — Being physically active reduces your cancer risk; Available at URL: https://www.cancer.org.au/cancer-information/causes-and-prevention/diet-and-exercise/move-your-body
- Physical Activity and Cancer Risk. Actual Knowledge and Possible Biological Mechanisms; Available at URL; Available at URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877262/
- Gut health: does exercise change your microbiome?; Available at URL: https://theconversation.com/gut-health-does-exercise-change-your-microbiome-140003
- Exercise and Prebiotic Fiber Provide Gut Microbiota-Driven Benefit in a Survivor to Germ-Free Mouse Translational Model of Breast Cancer; Available at URL: https://www.mdpi.com/2072-6694/14/11/2722/htm
- Exercise; Available at URL: https://www.cancervic.org.au/living-with-cancer/exercise/exercise-overview
- Physical Activity in Cancer Prevention and Survival: A Systematic Review; Available at URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6527123/
- Inactivity and Cancer Risk: The Latest Research; Available at URL: https://www.aicr.org/news/inactivity-and-cancer-risk-the-latest-research/
- Exercise During Cancer Treatment; Available at URL: https://www.cancer.net/survivorship/healthy-living/exercise-during-cancer-treatment
- How Does Exercise Affect The Gut Microbiome?; Available at URL: https://atlasbiomed.com/blog/how-does-exercise-affect-gut-microbiome/#:~:text=symptoms%20and%20conditions.-,What%20can%20exercise%20do%20for%20my%20microbiome%3F,acid%20synthesis%20and%20carbohydrate%20metabolism
- Interplay Between Exercise and Gut Microbiome in the Context of Human Health and Performance; https://www.frontiersin.org/articles/10.3389/fnut.2021.637010/full
- Trial to look at effect of home exercise on gut microbiome in cancer survivors; Available at URL: https://www.uab.edu/news/research/item/12428-trial-to-look-at-effect-of-home-exercise-on-gut-microbiome-in-cancer-survivors
