Running And Cancer

Picture by Eric Norris from Flickr

The common cold and flu are not the only illnesses that running can ward off. A running (or exercise) strengthened immune system can reduce the likelihood of a variety of illnesses, including many types of cancer.

A large Swedish study found that men who walked or cycled for at least 30 minutes a day had a 34 percent lower risk of dying of cancer compared to couch potatoes.

Researchers studying studying prostate cancer tumour growth in rats that exercise or were sedentary found that rats (like humans) divert blood flow to muscles when exercising. The researchers found a 200 percent increase in tumour blood flow during exercise.

When a tumour is flooded with oxygen, it's activity tends to slow (Jones et al, 2010). This actually leads to a rate of decelerated metastasis (spread of disease to other organs)

Another study by a different group of researchers showed that aerobic exercise leads to tissue returning to it's pre tumour state or ward off development of a more aggressive and dangerous cancer.

Greater blood flow and oxygen delivery to a tumour can possibly transport cancer fighting therapy to the tumour. Exercise increases blood flow by increasing blood pressure and pumping and by decreasing blood vessel constriction.

Exercise is also believed to help reduce cancer by other mechanisms. High insulin levels are associated with increased risk of cancer, and exercise helps reduce insulin levels. There are definitely other mechanisms by which exercise combats cancer that have not been discovered.

You don't have to wait to know these mechanisms to be discovered to get the cancer suppressing benefits of being a runner.

References

McCullough DJ, Nguyen LM et al (2013). Effects Of Exercise Training On Tumor Hypoxia And Vascular Function In The Rodent Preclinical Orthotopic Prostate Cancer Model. J Appl Physiol (1985). 115(12): 1846-54. DOI: 10.1152/japplphysiol.00949.2013.

McCullough DJ, Stabley JN et al (2014). Modulation Of Blood Flow, Hypoxia, And Vascular Function In Orthotopic Prostate Tumours During Exercise. J Natl Cancer Inst. 106(4): dju036. DOI: 10.1093/jnci/djuo36.

Orsini N, Mantzoros CS et al (2008). Association Of Physical Activity With Cancer Incidence, Mortality, And Survival: A Population-based Study Of Men. Br J Cancer. 98: 1864-1869. DOI: 10.1038/sj.bjc.6604354.

Jones LW, Viglianti BL et al (2010). Effect Of Aerobic Exercise On Tumor Physiology In An Animal Model Of Breast Cancer. J Appl Physiol (1985). 108(2): 343-348. DOI: 10.1152/japplphysiol.00424.2009.