The Impact of Exercise in Lowering Cancer Risk

Cancer has always been the deadliest disease up to date. Around the world, cancer is the biggest cause of mortality, contributing for nearly 10 million fatalities in the year 2020. There are roughly 400 000 new cases of cancer diagnosed in children each year. A significant gap between over-nutrition and low energy activity is a hallmark of modern times, especially in Western or Civilized countries. This imbalance continuously unsettles cellular, tissue, organ, and systemic homeostasis, hastening the start and increasing the risk of many types of cancer. Westerners' resting metabolic rates (the amount of energy our bodies use while at rest) are alarmingly lower than those of our Homo ancestors, and they're dropping fast.

Physical activity and cancer risk: what's known?

When it comes to cancer care, exercise is crucial, especially for preventing the disease, slowing its course, and bettering the quality of life for those who have battled the disease. A study including 430,000 adults found that engaging in regular physical activity during one's free time reduced the likelihood of developing multiple forms of cancer. The health of cancer survivors may also benefit from exercise because it has the potential to lessen the effects of risk factors like obesity and inflammation.

There was a 15% reduction in risk of bladder cancer among those who engaged in the greatest levels of leisure or professional physical activity compared to those who engaged in the lowest levels of exercise, according to a meta-analysis of 11 cohort studies published in 2014.

Number of studies indicate an inverse association between exercise and breast cancer, with a 20%-80% risk decrease for postmenopausal cancer and a lesser influence for premenopausal women. Exercising before and after menopause had a similar effect, reducing breast cancer risk by about 15–20% overall. Childhood and adolescent exercise may prevent breast cancer by reducing fat accumulation and sex hormone intake. Regular exercise has numerous positive consequences on health in maturity, and these benefits are amplified when children develop exercise routines and stick with them throughout life.

Aerobic and resistance training together can help lower cancer mortality

Leandro Rezende, a professor in the Department of Preventive Medicine at the Federal University of So Paulo's Medical School (EPM-UNIFESP) in Brazil, told Agência FAPESP that his study found evidence that muscle strength training can not only lower the risk of cancer and death from it, but that it has an even greater effect when combined with aerobic activities like walking, running, swimming, and cycling.

A thorough evaluation of epidemiological data found that regular muscular strengthening workouts in conjunction with aerobic activities can lower cancer mortality. Incorporating exercises such as squats, rows, planks, weight training, and so on into your routine will cut your risk of dying from cancer by 14 percent. It has been estimated that a 28% decrease in mortality could occur when these workouts are paired with aerobic activity.

The findings of the study also added credence to the (WHO) guidelines for adult aerobic exercise, which prescribe 75 to 150 minutes of strenuous activity per week in addition to 150 minutes of moderate exercise. Twice-weekly strength training is also recommended by the WHO.

Prostate Cancer and Exercise:

Prostate cancer is a multifaceted illness with distinct relationships between risk factors for overall nonaggressive disease and fatal disease. Among 988 cancer patients and 1,063 controls, regular strenuous exercise, and exercise throughout the first 18 years of life were found to reduce cancer risk. While work activity was related with lesser chance of advanced-stage prostate cancer, a large prospective analysis revealed no correlation between occupational or recreational exercise and prostate cancer incidence.

Physical activity has been linked to a reduction in fatigue, as well as gains in muscular strength, cardiorespiratory fitness, lean body mass, and overall health, all of which are beneficial in the management of adverse effects associated with prostate cancer treatment. Rectal toxicity was dramatically reduced in a group of 66 males getting radiotherapy after they walked for 30 minutes, three times a week, for 4 weeks. Resistance training reduced tiredness, improved quality of life, strength, triglycerides, and body fat among 121 men undergoing radiation and androgen suppression. Substantial reductions in waist size were observed after a 16-week intervention in yet another study, albeit with substantial attrition.

Delving into Exercise Oncology

The Edwin Smith Papyrus writings from ancient Egypt date back to 3000 BCE, and they depict a breast tumour that is "grave, for which there was no therapy." In 1761, J Hill of London published the first book on cancer prevention, in which he linked smoking to multiple cancers. The positive effects of exercise on health have been recognised for millennia, but the study of exercise's role in cancer prevention, treatment, and survival is a relatively new field of inquiry.

Exercise for health and cancer has been the subject of literature since classical era. Exercise's potential to reduce tumour growth has been suspected since the 1930s, and the first reference of its use in cancer prevention dates back more than a century. While the idea of exercise as a preventative measure and a therapeutic intervention has been around for a while, it was until recently considered very novel. Although it was only formally recognised in 2005, the area of exercise oncology has seen tremendous growth over the past decade.

Physical activity recommendations for people with cancer

Despite improvements in cancer survival rates, people in Australia living with a cancer diagnosis have risen sharply over the past decade. The volume of high-quality, randomised, controlled trials published that assess the impact of exercise on a range of results associated to cancer at every stage of the disease's progression, from prognosis to death, has increased exponentially.

There is considerable evidence that exercise improves active cancer treatment, but little evidence that the timing of an exercise session helps. The evidence base is conducted for all cancer kinds, cancer-specific outcomes, and alternative exercise prescriptions is assessed in perspective of its benefits and drawbacks and implemented in practise with standard exercise prescription principles. This enhances the lives of cancer patients.

For the exercise prescription the process includes patient assessment, analyze health problems, determine patient aptitude, and establish whether a certain action is appropriate. Medical permission for assessing and prescribing exercise for cancer patients is controversial. A universal medical clearance requirement for all cancer patients hinders exercise prescribing.

Moreover, given the well-documented risks associated with inactivity, a tailored fitness programme would only be inappropriate in exceptional conditions. Targeted exercise prescription before, during, and after cancer care is unlikely to be identified by all treating doctors, which may lead to a scenario where the most in need are the least likely to acquire medical clearance.

Bottom line

Physical activity's significance in cancer prevention has been defined in the last decade. Recent studies suggest that physical activity may reduce the risk of oesophageal, liver, bladder, gastric, and renal cancers in addition to colon, breast, and endometrial cancers. Pancreatic, ovarian, head and neck, prostate, and hematologic malignancies may also be linked to physical inactivity, while the information is insufficient to draw firm conclusions.

A few recent findings demonstrates that excessive sedentary time may raise the risk of colon and endometrial cancer. More study is required before we can reliably and completely prescribe exercise for cancer prevention, despite all that we have learnt. Sedentary behaviour suggestions beyond "exercise more, sit less" require more research. The American Cancer Society's cancer prevention guidelines and the Physical Activity Guidelines for Americans' minimal activity prescriptions may minimize cancer risk.

References

American Cancer Society. (2018). American Cancer Society Guideline for Diet and Physical Activity for Cancer Prevention. Cancer.org; American Cancer Society. https://www.cancer.org/healthy/eat-healthy-get-active/acs-guidelines-nutrition-physical-activity-cancer-prevention.html

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Exercise can now be prescribed like medicine for people with and beyond cancer. (2019, September 16). EurekAlert! https://www.eurekalert.org/news-releases/658481

Hayes, B. D., Brady, L., Pollak, M., & Finn, S. P. (2016). Exercise and Prostate Cancer: Evidence and Proposed Mechanisms for Disease Modification. Cancer Epidemiology Biomarkers & Prevention, 25(9), 1281–1288. https://doi.org/10.1158/1055-9965.epi-16-0223

Hayes, S. C., Newton, R. U., Spence, R. R., & Galvão, D. A. (2019). The Exercise and Sports Science Australia position statement: Exercise medicine in cancer management. Journal of Science and Medicine in Sport, 22(11), 1175–1199. https://doi.org/10.1016/j.jsams.2019.05.003

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McKie, R. (2021, February 14). Exercise can help prevent cancers, new research finds. The Guardian. https://www.theguardian.com/society/2021/feb/14/exercise-can-help-prevent-cancers-new-research-finds

Nascimento, W., Ferrari, G., Martins, C. B., Rey-Lopez, J. P., Izquierdo, M., Lee, D. H., Giovannucci, E. L., & Rezende, L. F. M. (2021). Muscle-strengthening activities and cancer incidence and mortality: a systematic review and meta-analysis of observational studies. International Journal of Behavioral Nutrition and Physical Activity, 18(1). https://doi.org/10.1186/s12966-021-01142-7

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