Race for life - reducing the effects of cancer in more ways than one

Exercise contributes to the prevention of cancer, it's a fact. But have you ever wondered how?

In just over a month, 'Race for Life' will be holding events all over the country in a bid to raise as much money as possible. The participants will walk, jog or run 5-10km and the main benefactor of the thousands of women taking up the challenge is Cancer Research UK. 

All the money raised will be used to help find innovative ways of curing and preventing cancer in the general population, but there is something very cheap, simple and easy that you can do to reduce your likelihood of developing the illness. 

EXERCISE!!!!

But what are the potential mechanisms for this effect?

1. Sex Hormones

• Exercise helps to reduce circulating levels of oestrogen and progesterone, which has been shown to decrease the incidence of breast cancer in all ages. 
• This reduction is suggested to be as a result of improved oestrogen metabolism, clearing excess oestrogens more quickly. 
• An alteration in circulating male sex hormones results in lower incidence of male cancers such as prostate and testicular cancer. 

2. Immune Function

• It has been known for a long time that exercise improves immune function, both it's responsiveness and efficiency. Although most cancers are not truly immunogenic, cancers are to some degree susceptible to control by innate immune mechanisms.
• A stronger immune system results in a greater clearance of tumour cells before they get the chance to proliferate, also it deals with any cancer causing viruses before they have a chance to cause any damage. 
• The elderly should pay particularly close attention to this effect, as the immune system naturally declines as we get older. Physical activity can help to prevent this decline and maintain a robust natural defence system. 

3. Oxidative Damage from Free Radicals 

• Oxidative damage occurs when incomplete molecules (free radicals) come in to contact with cell structures, causing them damage and potentially resulting in cancerous mutations. 
• Exercise may increase the clearance of these free radicals, resulting in a reduced incidence of tumour development. 

4. Insulin

• Chronically elevated insulin levels is associated with a significant increase in cancer risk.
• Exercise increases insulin sensitivity, which in turn reduces the amount of circulating insulin in the blood. This has been suggested to be a main contributor to the effect of exercise on cancer. 

5. Body Composition

• Energy balance (energy intake - energy expenditure) has been long associated with cancer risk. In the same vein, caloric restriction has been shown to reduce the incidence of cancer. 
• The result of a high energy balance - obesity - has also been linked to developing cancer, 
• Therefore reducing body mass through increased energy expenditure should reduce the risk of cancer. 

With all of this in mind it is important to note that none of these mechanisms are totally conclusive. They are just educated suggestions with some empirical back up. The only thing that is certain is that more exercise results in a reduced risk of cancer. 

So training for the 'Race for life' may be as beneficial to the prevention of cancer as the money you donate. 

GO FOR IT!

Refs
http://www.setantacollege.com/wp-content/uploads/Journal_db/Physical%20Activity%20and%20Cancer.pdf