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The Short Science behind Exercise and Canccer

Dr Brian Kunakon, 30th June 2021

We always hear about the benefits of exercising for the prevention of cancer and for patients undergoing cancer treatments. However, the practicality of seeing a cancer patient exercise seems to be close to non-existent. How exactly does exercise will help with cancer patients? Is it really just the endorphins being released to help relieve stress to help create a better quality of life. Let’s dive into the mechanisms found in research.

Just as a brainteaser, which of the following group of people would benefit most from exercising:

a. People without cancer

b. People undergoing chemotherapy, radiation, and/or immunotherapy

c. People who have completed treatment

Fun Fact! Exercise releases Endorphins?

For decades, we keep hearing about the “runner’s high” that many runners would experience during their runs. This is the state of relaxing euphoria after intense or lengthy exercise. It turns out that scientists discovered lately that endorphins are not responsible for the euphoric state. Endorphins are a type of opiod released by the body in certain states and can be induced by pharmaceuticals. During the study, participants were given opiod blockers and yet, participants still experience the state of euphoria. Upon checking their endocannabinoid markers in blood, they found that this is the substance responsible for the state of euphoria. Endocannabinoids are molecules released when an individual is exposed to the once very illegal substance called marijuana. Exercise is a natural process in which we release cannabinoids without having to be exposed to the actual substance!

According to Hojman et al., there is a molecular role in cancer exercise in both prevention and treatment. In an untrained body, the immune cells are stagnant because there is not enough movements to help stimulate blood flow towards the tumor. As a person starts exercising, the immune cells are able to reach the foreign substance easier leading to an immune reaction that may make the person feel sick. Can we all relate to this? This is where most people decide not to exercise ever again. Then, as the body keeps training, the body reaches a chronic state of training adaptation, which allows the immune cells to circulate to places whenever and wherever more freely than the stagnant status.

Hojman et al, continues to explain how during treatment, it does not apply only to the immune cells, but also any therapy given to the patient that is under the chronic training adaption state. By allowing more circiulation to the body, the side effects of treatments are lessened and enhances tolerance to drugs. For those unfamiliar to chemotherapy, cancer patients do experience the harsh side effects such as fatigue, nausea, vomiting and lack of appetite. Due to the lessened side effects and increase in exposure of the tumor to the drugs due to increase blood circulation, exercise helps promote overall treatment efficacy.

Which of the following group of people would benefit most from exercising:

a. People without cancer

b. People undergoing chemotherapy, radiation, and/or immunotherapy

c. People who have completed treatment

All of the above!

The chronic training state requires consistency and frequency to attain. The small habitual changes matters more than the big sudden changes especially in the realm of health. The accumulation of small changes will eventually turn into a big change that is longer lasting that the sudden big changes. With that being said, exercising to prevent cancer is a better solution than waiting to get sick then make the small changes. For those of you who are diagnosed with cancer, take this opportunity to empower your community to exercise as a preventive measure and start with the small changes.

Now that we are all convinced that exercise is important for both cancer prevention and treatment, the only thing left is, can any cancer patient just start exercising on their own? This is generally recommended, since we know that injuries may occur to a healthy person; hence, in a cancer patient this may become problematic. It is then important to identify Cancer Exercise Specialists that are trained to recognize the size effects of cancer treatments and to help facilitate training in the safest and most effective method possible.


Dr Brian Kunakon

Naturopathic Doctor - Bumrungrad International Hospital, Bangkok

Cancer Exercise Specialist & FAA Master Trainer


Hojman, Pernille & Gehl, Julie & Christensen, Jesper Frank & Pedersen, Bente. (2017). Molecular Mechanisms Linking Exercise to Cancer Prevention and Treatment. Cell Metabolism. 27. 10.1016/j.cmet.2017.09.015

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