Exercise: an anti-cancer agent
Abstract
Elevated levels of insulin and insulin-like growth factor (IGF) have been implicated as risk factors for cancer, and indeed, fasting and fasting-mimicking diet appear to promote protection of normal cells and induce cancer cell death.1 It is for this reason that it is believed that these two hormones are also the leading candidates to explain the correlation between obese and diabetic individuals and cancer risk.1 Moreover, such individuals are less likely to have a good prognosis under such circumstances than leaner equivalents.1,2
The concern is that cancer in young adults is occurring with increasing frequency in developed countries and this may be associated with increasing population levels of overweight and obesity, which are reaching pandemic proportions.3The potential for a catastrophic increase in obesity‐associated cancers in young adults is frightening.3
The modern trend for increasing sedentariness also prompts additional related concerns in that exercise has been shown to have wide-ranging benefits not only for the body and the mind, but also for the immune system.4
It has been demonstrated that immune system effectiveness declines by circa 2-3% a year from the second decade of life, which is why the elderly are more susceptible to infections, auto-immune disorders and cancer.4 T-cells are effective markers of immune function and it has been shown that vigorous activity preserves immune function such that individuals in their seventh and eighth decades of life have immune function comparable to twenty-year olds.4
More specifically endurance cyclists were shown to have significantly higher serum levels of the thymoprotective cytokine IL‐7 and lower IL‐6, which promotes thymic atrophy. Additional evidence of reduced immunesenescence, included lower Th17 polarization and higher B regulatory cell frequency than inactive peers. However, physical activity did not protect against all aspects of immunesenescence: CD28−veCD57+ve senescent CD8 T‐cell frequency did not differ between cyclists and inactive peers.4
In physically active elderly individuals, preserved immune function may also allow better vaccine responses, such as to seasonal influenza.4 The same study group was incidentally also shown not lose muscle mass or strength, and did not experience an increase in body fat, all of which are usually associated with the ageing process.5
In short, keeping fit and exercising into old age reduces cancer risk.
References
- Buono R, Longo VD. Starvation, Stress Resistance, and Cancer. Trends Endocrinol Metab. 2018 Apr;29(4):271-280.
- Taubes G. Cancer research. Unraveling the obesity-cancer connection. Science. 2012 Jan 6;335(6064):28, 30-2.
- Berger NA. Young Adult Cancer: Influence of the Obesity Pandemic. Obesity (Silver Spring). 2018 Apr;26(4):641-650.
- Duggal NA, Pollock RD, Lazarus NR, Harridge S, Lord JM. Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging cell. 2018 Apr;17(2):e12750.
Figure
Test image
License
The Editorial Board retains the copyright of all material published in the Malta Medical Journal. Any reprint in any form of any part will require permission from the Editorial Board. Material submitted to the Editorial Board will not be returned, unless specifically requested.
