Can Exercise Prevent Cancer?

Why This Happens

Being physically active can change the levels of some hormones, including oestrogen and insulin in the blood. Physical activity can lower the level of oestrogen which is thought to fuel the development of many breast and womb cancers, so reducing the levels of this hormone could help to reduce the risk. Insulin is very important in controlling how our bodies use and store energy from food so scientists think insulin can turn on signals that tell cells to multiply. Because cancer starts when cells multiply out of control, lowering insulin levels could help stop some types of cancer developing. Lower oestrogen levels among physically active women with breast cancer could potentially improve survival, although not much data exists to support this at the moment.

Colon Cancer

There are two main ways that physical activity lowers the risk of developing colon cancer.

1. Physical activity helps food move through our bowels more quickly. This reduces the amount of time that the lining of the bowel is in contact with any harmful chemicals. This is especially important for alcohol, red and processed meat because there's less chance of damage to the colon that could lead to cancer.
2. Physical activity can also reduce inflammation in our bowels. When constantly inflamed, the cells in the bowel have to multiply much more frequently than usual, to replace dead and damaged cells, which means there is more chance of cancer developing. Being physically active helps to keep inflammation under control in our bowel, reducing the risk of cancer developing. Physically active men and women have about a 30-40% reduction in the risk of developing colon cancer, compared with those of us who are inactive.

Prostate Cancer

Dr. Stacey Kenfield, a Prostate Cancer Foundation Young Investigator first-authored a study published in the Journal of Clinical Oncology in 2011 that looked at physical activity and outcomes for men diagnosed with prostate cancer. That study found that:

• Men who walked briskly for 90 minutes or more per week lower their risk of death from any cause by 46% compared to men who men who walked less quickly and less often.

• Men who exercised vigorously (e.g., biking, tennis, jogging, swimming) three or more hours per week had a 61% lower risk of death from prostate cancer compared to men who exercised vigorously less than one hour per week.

• Both non-vigorous and vigorous activity lowed men’s risk of death from any cause.

3 easy ways to become more active

1. Spend less time sitting

In Ireland, we're spending more and more time sitting down. Many of us spend most of our day sitting down going from our desk at work to the couch at home, often driving or taking public transport in between. Get up and move around to break up periods of sitting time:

• Get up and change the TV channel, instead of using the remote

• Break up sitting time by doing bits of housework or chores, like the washing up or putting the rubbish out

• At work, visit a colleague's desk rather than calling or sending an email

• Stand up and move around every so often - go and stick the kettle on or collect post or printing

2. Walk more

Walking more is a great way to increase your level of physical activity. It's easy to fit into your daily routine. You don't need any special clothing or equipment and it's free. You don't have to walk for a long time - every little bit adds up:

• If you can, walk to or from work, if it's too far, try walking part of the journey by getting off public transport a stop earlier or using a car park that's slightly further away.

• Take the stairs instead of the lift and try to walk up escalators. If you work on a high floor, build up to climbing all the floors as you get fitter.

• Go for a short walk at lunch time. Spending time away from a computer screen will give your eyes a rest and help you feel more refreshed too. For shorter journeys, walk rather than driving or using public transport. You could save some money and you might even find it's quicker.

3. Moderate activity

Activity doesn't just mean sport and exercise. Anything that makes you a bit warmer and slightly out of breath counts as moderate activity, including:

• Cycling or brisk walking

• Heavy gardening

• Household tasks like vacuuming or DIY

No research will ever suggest that a sedentary life is healthy but then on the other hand, it is impossible to say that there is any one cause of cancer. Since it can affect anybody at any time, financial provision is a great idea.

_{The article was written by the MedOnline Medical Team. MedOnline is an interactive web/mobile clinic. The views expressed in this article are those of MedOnline and do not necessarily reflect the views of AIG Europe Limited.}

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