How Does Exercise Help Prevent Cancer? - 9 Key Mechanisms
We all know that exercise is good for us but do we really understand why it is so good for us? And with respect to cancer - what do we actually know - how does exercise help prevent cancer?
For anyone that is affected by cancer (and that includes me), and also for those looking at ways of preventing cancer occurring in the first place, it is crucial that we understand this so that we make sure exercise and movement becomes part of our daily routine. It is most certainly a health promoting habit that may just help to save our lives.
It’s important that we know what we can do to help ourselves.
The word ‘cancer’ conjures up fear for many, but it shouldn’t be this way. The science is pretty clear and the evidence is growing rapidly, it is possible to create a body in which cancer is much less likely to grow, develop and thrive, and we can do this by modifying our behaviours, diet and lifestyles choices. The traditional ‘Western style’ diet and lifestyle that has developed over the last few hundred years, is just not conducive to good health.
So how can do this? There are many areas that we can modify to stack the deck more in our favour, with exercise being a major modifiable factor. Simply being told that exercise is good for us doesn’t seem to be enough though, if it was then more people would be out there exercising each and every day, yet the data shows that the majority of people are not. So hopefully by explaining some of the key physiological mechanisms contributing to why exercise helps prevent cancer, I can provide the next level of information that you may need to encourage and inspire you to pop on your trainers and to get moving*.
“I love exercise, it helps keep me healthy, makes me feel happier, and ensures that I stay physically strong.
As a breast cancer thriver, it is especially pleasing to know that each time I put my gear on and head out for a run or to the gym, I’m also protecting myself against any potential recurrence.”
If you would like to understand more about which other diet and lifestyle modifications can significantly reduce your risk of cancer recurrence, support you through your cancer journey, and reduce your risk of recurrence, then register for our 90 Day Cancer Support Programme. TThrough this programme we help empower you through increased knowledge, how to implement the necessary changes in a sustainable manner. Life long changes that will make a huge difference to your overall health, and disease risk profile. We aim to:
Improve your knowledge of what to eat & why: Giving you greater confidence and control over your potential outcome.
Support your immune system: To keep you feeling well, improve your potential outcome, and to reduce the risk of cancer recurrence.
Improve your energy levels and mood: Thereby improving your overall sense of wellbeing, and enabling you to put your energy into improving your health.
Optimise your nutritional status: To keep you feeling well, improve your potential outcome, and to reduce your risk of cancer recurrence.
Improve your healing after surgery: Through better nutritional choices.
Support your gut health: To reduce any adverse digestive symptoms and side effects, and to improve nutrient absorption.
Maintain your muscle mass: To keep you physically strong, better able to cope with any treatments offered, and improve your potential outcome.
Minimise treatment side effects: Aiming to mitigate the negative impact of any standard treatment received.
Reduce your risk of cancer recurrence: Through better nutrition and lifestyle choices.
Improve your quality of life: Through holistic support, helping you to thrive long after your cancer diagnosis.
If you don’t have an active or recent cancer diagnosis and are interested in ensuring that you stay this way, then we can help support you too. Check out our 90 Day Health and Wellbeing programme for more information.
How Does Exercise Help Prevent Cancer?
Exercise helps prevent cancer in numerous ways, with studies demonstrating a myriad of physiological and psychological benefits from moderate regular exercise. Detailed below are 9 key mechanisms explaining how exercise helps prevent cancer.
1) Exercise helps you to maintain a healthy weight
Being overweight is possibly your biggest risk factor for cancer. Body fat is inflammatory and produces hormones that have been demonstrated to contribute to a pro-cancer physiology. Overweight and obese individuals have increased rates of cancer and cancer recurrence.
In the UK:
Overweight and obesity is the second biggest cause of cancer in the UK – causing more than 1 in 20 cancer cases (1).
The risk is higher the more overweight you are and the longer you are overweight for (1).
Keeping a healthy weight reduces the risk of 13 different types of cancer (1).
2) Exercise reduces body fat and increases lean muscle mass.
Maintaining lean muscle mass is critical for cancer survival with the loss of muscle mass being a risk factor for cancer progression. This is especially important during and after cancer treatment as the treatment itself can contribute to significant weight and muscle loss in cancer patients.
It is key that you work to ensure that any muscle loss is minimised and I recommend that anyone recently diagnosed with cancer works with a suitably qualified nutritional therapist and PT to reduce their risk of significant muscle mass loss.
Also be conscious that a stable weight does not necessarily equate to maintained muscle mass, as muscle mass can easily be replaced by fat with poor food choices and reduced exercise, and as we know excess body fat contributes to a pro-cancer state.
Exercise reduces body fat and increases lean muscle mass.
Exercise helps to keep bones strong, and with healthy, strong bones there is less bone loss and a reduced risk of fractures. Additionally, healthy bone is more resistant to cancer cell invasion (i.e. bone metastases) and reduces risk of cancer spreading to the bones.
I myself lost almost all my lean muscle mass in the months following chemotherapy treatment, which I believe is the fundamental reason why I had a sacral stress fracture subsequently. With appropriate and sufficient nutrition and exercise during and after chemo, I could have retained more muscle mass and believe that I could have avoided this fracture.
3) Exercise supports normal blood sugar metabolism, normal insulin signalling, and reduces your risk of diabetes
Cancer cells preferentially utilise sugar as fuel, therefore the more sugary the blood the more readily available fuel there is for cancer cell growth. Consequently, pre-diabetics with insulin resistance or metabolic syndrome and diabetics with chronically high blood sugar have increased risk of cancer and cancer progression.
Exercise influences hormone signalling to normalise blood sugar metabolism.
Exercise helps to prevent high blood levels of insulin, which has been linked to cancer development and progression** (2). However, be wary of very intense exercise as this can trigger the release of cortisol, a hormone that increases blood sugar.
4) Exercise strengthens the immune system
Research supports the link between regular exercise** and a strong immune system. Exercise has been shown to increase the production of immune cells, including Natural Killer Cells (NKCs), which target both cancer and viral cells.
5) Exercise supports healthy hormone levels
Exercise also reduces your risk of cancer through its positive impact on various hormone levels within the body.
Exercise lowers insulin and Insulin Like Growth Factor-1 (IGF-1) levels, both of which have been associated with cancer development and progression (2).
Exercise tends to lead to reduced body fat, which in turn leads to reduced oestrogen levels, as fat, especially fat around the middle, produces oestrogen. Therefore, the greater the level of body fat, the greater the levels of circulating oestrogen, which is linked to breast, uterine and prostate cancers.
6) Exercise improves digestive processes
Studies support exercise induced improvements to digestive processes which will reduce your risk of cancers of the lower digestive tract (e.g. bowel, colon and rectal cancer - note these names are often used interchangeably).
Exercise alters the metabolism of bile acids, decreasing exposure of the gastrointestinal tract to these suspected carcinogens (3, 4)
Exercise reduces the time it takes for food to travel through the digestive system, decreasing gastrointestinal tract exposure to possible carcinogens
7) Exercise promotes healthy mood and emotions
Exercise has been demonstrated to positively impact mood and emotions, and can reduce feelings of depression, anxiety and fatigue, all feelings commonly experienced following a cancer diagnosis and any subsequent treatment.
Many studies have also shown that physical activity during and after cancer treatment can help manage these mental health struggles, alongside improving patients’ self-esteem and overall mood (5).
For myself, there is a direct correlation between my ability to exercise and my feelings of wellbeing. When I can’t exercise for whatever reason, it gets me down. Consequently, it was essential for my mental health that I could exercise throughout my cancer treatment and beyond. I obviously had to adapt the type and intensity of my exercise, generally opting for yoga, walking, gentle cycling or jogging in the main. I also couldn’t swim in a pool for a long time as my immune system was so dysregulated that the chlorine caused significant allergic type responses. Thankfully, my immune system is now much more in balance so I can swim in a pool again.
8) Exercise can form part of your stress management strategy
Exercise has been shown to reduce psychological stress, anxiety and tension, with regular exercise being associated with improved resilience to acute stress (7).
Furthermore, regular moderate exercise can counter the negative impact on the immune system of chronic stress by bolstering your Natural Killer Cells - immune cells which fight cancer and infection.
9) Exercise contributes to an anti-cancer, health promoting lifestyle
Cancer patients who exercise regularly:
Are better able to complete their prescribed treatments and suffer from fewer side effects compared to those who are sedentary.
Have better overall rates of survival and lower rates of recurrence.
Exercise helps prevent cancer: a key component in enabling you to create a body in which cancer cannot thrive.
How much physical activity is recommended?
For substantial health benefits and to reduce the risk of chronic diseases, including cancer, it is recommended that adults engage in* (7):
150 to 300 minutes of moderate-intensity aerobic activity, 75 to 100 minutes of vigorous aerobic activity, or an equivalent combination of each intensity each week. This physical activity can be done in episodes of any length.
Muscle-strengthening activities at least 2 days a week
Balance training, in addition to aerobic and muscle-strengthening activity.
Exercise supported by better nutrition are powerful tools in the prevention of cancer.
Making better choices about how much you move your body, and what you nourish your body with each and every day, can greatly reduce your risk of cancer and improve the chances of a positive outcome for those already with a diagnosis.
As discussed here, and supported by compelling evidence, exercise has many benefits which help both prevent cancer occurring in the first place, and also to shift a body from a diseased state back to one of health.
However, I also appreciate from my own experience that the information available regarding cancer can be a little overwhelming. There is so much conflicting information out there regarding what can help protect us from cancer, that you may not know what to believe anymore. It can be especially challenging for those with a recent diagnoses, who may find themselves not knowing what to do for the best.
I have been in your situation and I too felt totally overwhelmed. If this is you and you would like some help navigating through this challenging time then please look at how I can help you.
There are so many positive steps that you can take to improve your situation. I can help you determine where best to focus, to introduce more health promoting habits, and support you on your journey back to health.
Take a look at our 90 day programme for more information as to how I can support you, or alternatively, if you have any questions then send me a message and I will get back to you as soon as possible.
Sarah Eglin: Registered Nutritional Therapy Practitioner (mBANT) and breast cancer ‘thriver’
If you would like to read more about my personal experience with breast cancer and my journey back to great health then please click on the following links for more in depth information.
You can also join my Facebook group - Become a Cancer ‘Thriver’ and follow me on Facebook or Instagram.
Notes
*Check with your doctor before starting any new training regime. If you are currently in the midst of cancer treatment then extra care must be taken when considering the appropriate level of exercise for you. Please consult your doctor and an appropriately qualified physiotherapist (PT) first.
**It should be noted that while moderate exercise can boost the immune system, intense exercise or prolonged exercise, as seen in some endurance athletes can have the opposite effect.
References
(1) Cancer Research UK. (2023). ‘How does obesity cause cancer?’ Available at https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/bodyweight-and-cancer/how-does-obesity-cause-cancer#:~:text=Overweight%20and%20obesity%20is%20the,13%20different%20types%20of%20cancer. (Accessed 18 April 2023)
(2) Winzer BM et al. (2011). 'Physical activity and cancer prevention: a systematic review of clinical trials.' Cancer Causes and Control. Vol 22(6). pp811-826. [PubMed Abstract]
(3) Wertheim BC et al. (2009) ‘Physical activity as a determinant of fecal bile acid levels.’ Cancer Epidemiology, Biomarkers & Prevention. Vol 18(5). pp1591-1598. [PubMed Abstract]
(4) Bernstein H et al. (2005). ‘Bile acids as carcinogens in human gastrointestinal cancers.’ Mutation Research. Vol 589(1). pp47-65. [PubMed Abstract]
(5) Mishra SI et al. (2012). ‘Exercise interventions on health-related quality of life for people with cancer during active treatment.’ Cochrane Database Syst Rev. Aug 15; 2012(8):CD008465. doi: 10.1002/14651858.CD008465.pub2. PMID: 22895974; PMCID: PMC7389071.
(6) Childs E, de Wit H. (2014). ‘Regular exercise is associated with emotional resilience to acute stress in healthy adults.’ Front Physiol. Vol 5:161. doi: 10.3389/fphys.2014.00161. PMID: 24822048; PMCID: PMC4013452.
(7) National Cancer Institute. (2023). ‘Physical Activity and Cancer.’ Available at https://www.cancer.gov/about-cancer/causes-prevention/risk/obesity/physical-activity-fact-sheet . (Accessed 11 April 2023)