Physical activity as cancer prevention

Dr Jacolene Kroff educates us on the underlying mechanism of how physical activity prevents cancer.

The 2018 Physical Activity Guidelines Advisory Committee stated there is strong evidence that physical activity lowers the risk of colon-, breast-, kidney-, endometrium-, bladder-, stomach and oesophageal cancers.³ 

To understand the underlying mechanism of how physical activity prevents cancer, you need to know how cancer comes about. In all cells, the genetic make-up will determine how that cell will grow, develop and function within the body. 

However, in certain cases something can go wrong with the programming of the cell responsible for the regulation of cell growth. Once this happens, normal cells mutate. 

Outside stimulants, such as tobacco smoke, and factors in the cell (hormones) will help the growth of mutated cells. Because the genes responsible for cell growth and tumour suppressing aren’t working correctly, these cells grow and multiply uncontrollably, forming a large mass of cells, called a tumour. 

Furthermore, this tumour becomes malignant, and resistant against your immune system that wants to destroy it. 

It grows its own blood vessels, keeps on multiplying in cell numbers, and starts to use a large portion of the energy from the food you eat. 

It becomes large enough to invade surrounding organs and/or layers. Once blood vessels are formed, some pieces can break off and travel through the blood to other parts of the body. Normally the lungs, bone, brain, kidneys and liver.³ Here the cancerous cells will infiltrate the tissues of these organs and repeat the same cycle as before. At this stage, the cancer has metastasised.  

How exactly does physical activity prevent cancer?

Exercise is believed to affect the internal environment of the cell to suppress the growth of a tumour. 

There is evidence that physical activity reduces the cell’s capacity for multiplying. It activates the genetic programming accountable for suppressing tumours, and increases markers of programmed cell death (essential for normal cell growth). All three functions above are the exact processes needed to fight against the development of cancer.

Physical activity also improves blood flow in the poorly constructed blood vessels in the tumour, helping chemotherapies and the immune system to fight the tumour. The latter explains the meaningfulness of exercise during cancer treatment. 

Another benefit is that exercise can also help improve your emotional well-being which in return will help you stick to your cancer treatment regime.³

How much exercise must I do?

Research shows that leisure time activities and occupational physical activity may confer a lower risk for some cancers. Thus, doing planned exercise (gym, running, cycling) or participating in a specific sport (local sports club) falls under leisure time activities. Commuting by foot or bicycle to and from work, and stand and/or walk at work regularly falls under occupational physical activity. 

With regards to the amount and intensity of exercise, most evidence suggests that more intense exercise is associated with lower risk. The current physical activity guidelines recommend 150 to 300 minutes per week (at least 30 mins or exercise on most days (5) of the week) of moderate physical activity, or 75 to 150 minutes per week of vigorous intensity exercise (at least 25 mins three times a week). 

Many research studies agree that the combination of moderate to vigorous intensity exercise is associated with reduced risk of many different cancers. Based on the inclusion of vigorous exercise, a combination of alternating aerobic and resistance training would be best practice to elicit moderate and vigorous exercise intensities. 

Must I exercise for the rest of my life?

Most evidence suggests that regular exercise early, later and throughout adulthood is associated with lower risk for some cancers. However, the evidence is not clear cut. Some studies have shown that recent physical activity during adulthood is linked to lower risk for renal cancer compared to physical activity during early lifespan.³ 

Only regular exercise over a long period of time will lower your risk for cancer that will most likely become a health risk later in life. Thus, investment now will pay off later in life. 

Can anyone help me exercise?

Many individuals find it difficult to adhere to a specific exercise regime. Especially because the underlying benefits have no immediate reward. Plus, many aren’t sure how, when, or for how long to exercise. These challenges can be overcome by consulting a biokineticist. 

Biokineticists are specifically equipped to prescribe physical activity and supervise individuals for the management and prevention of non-communicable diseases, including cancer. 

References 

1. Bray F, Ferlay j, Soerjomataram I, Siegel R, Torre L, Jemal A. Global Cancer Statistics 2018: GLOBOCAN Estimates of Incidence and Mortality of Worldwide for 36 Cancers in 185 Countries CA: Cancer J Clin 2018, 68:394-424. 

2. Kaninjing ET, Dagne G, Atawodi SE, Alibi A, Ogunlana O, Patrick T. Adegun PT, Nggada H, Okoye I, Omonisi AE, Faruk M, Bassey IE, Sulaiman FA, Askins N, Nkegoum B, Popoola AA, Sowumni AC, Oladoyinbo C, Omolara A. Fatiregun OA, Jibrin P, Emeka E. Iweala EE, Wole Kukoyi W, Kayode Adeniji K, Salako A, Okpala I, Okoro U, Mbadiwe O, Dogo HM, Gali M, & Odedina FT. Modifiable Risk Factors Implicated Prostate Cancer Mortality and Morbidity among Nigerian and Cameroonian Men. Cancer Health Disparities 2019, doi: 10.9777/chd.2019.1002

3. Patel AV, Friedenreich CM, Moore SC, Hayes SC, Silver JK, Cmapbell KL, Winters-Stone K, Gerber LH, George SM, Fulton JE, Denlinger C, Morris GS, Hue T, Schimitz KH & Matthews CE. Medicine and Science in Sports and Exercise 2019, 51(11):2391 – 2402.

This article is sponsored by Ferring Pharmaceuticals. The content and opinions expressed are entirely the medical expert’s own work and not influenced by Ferring in any way.

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