Fight back with fitness

Regular physical activity reduces the risk of cancer, so what are you waiting for? Get moving - and keep it up, for life

JILL BARKER, The Gazette, October 6, 2008

Chalk up another reason to exercise. More and more research suggests that physical activity plays a key role in reducing the risk of some forms of cancer. That's important news, considering that an estimated 166,400 Canadians will be given a diagnosis of cancer in 2008.

How does exercise affect cancer risk? Scientists aren't sure. Does exercise make its mark at the cellular or hormonal level or are exercise fanatics just that much younger, slimmer and healthier than the average couch potato? According to the American Cancer Society, obesity, inactivity and an unhealthy diet are second only to tobacco use when it comes to major risk factors for cancer.

Simply stated, cancer is the spread of abnormal cells within the body. Men have a 45 per cent probability of developing cancer during their lifetime. For women the probability is closer to 40 per cent. Statistically, approximately one in four Canadians will die from the disease.

Breast cancer is the most prevalent of cancers among women and prostate cancer is No. 1 among men. Lung cancer is the biggest killer of both sexes.

So while October is generally the month Canadians focus on breast cancer, it's also a good time to take a look at how to reduce the risk of all forms of a disease that is expected to take 73,800 Canadian lives before the year is out.

Some risks are unavoidable - like a family history of cancer - but about one third of all cancers can be prevented by healthy lifestyle changes. Identifying those preventable factors and changing high risk behaviour is a step in the right direction for Canadians who want to be proactive in the fight against cancer.

Some of the risks, like obesity and inactivity, can be addressed through regular exercise. Others, like smoking, sun exposure, poor nutrition and dietary habits can be combated by committing to a healthy lifestyle that includes physical activity.

The amount of exercise needed to cut the risk of cancer isn't out of reach for the average Canadian. The American Cancer Society calls for 30 minutes of brisk activity five days a week for general cancer prevention and 45 to 60 minute bouts of exercise five days a week to further reduce the risk of colon and breast cancer.

(The Canadian Cancer Society doesn't publish guidelines for how long or how hard to exercise to reduce cancer risk).

If you delve a little further, however, and take a look at some of the published research into exercise and cancer prevention, the data on exercise intensity and duration vary significantly. This kind of conflicting data doesn't mean that the scientific community is unsure about the importance of exercise. Both the Canadian and American Cancer Societies list regular physical activity as a cancer prevention tool. The takeaway message for the average Canadian is consistent and clear - you gotta get moving - daily.

According to the U.S. National Cancer Institute, physically active women have a 40-per-cent reduced risk of developing breast cancer and physically active men have a 10 to 30-per-cent reduced risk of developing prostate cancer.

That same get-moving credo applies to anyone who carries excess weight - that, at obese levels, increases the risk of cancer of the colon, endometrium, esophagus, kidney, breast among post menopausal women and other organs. So, burning extra calories daily reduces body fat.

Regular physical activity is also advised for those already living with cancer. The most recent studies show that maintaining regular physical activity during cancer treatments can reduce the risk of cancer recurrence. A study of American nurses found that breast cancer patients who walked or performed other types of moderate exercise for three to five hours a week were about 50-per-cent less likely to die than their sedentary breast cancer counterparts.

If those numbers are too big for you, consider the suggestion that any exercise is better than none at all. Even walking one hour a week can increase the odds of surviving breast cancer. And if you can hang in there or work your way up to three to five hours of moderate physical activity a week, the level of protection further increases.

The same goes for other types of cancer. A little bit of exercise is better than none.

The good news then is that it doesn't take Herculean amounts of exercise to reap the benefits of reduced cancer risk. What it does take is a commitment to keep active for the rest of your life.

And while you shouldn't confuse the message by thinking that regular exercise is your ticket to living cancer free, you should feel confident enough to bet the farm that going for a brisk 30-60 minute walk, run, swim or cycle most days of the week is an easy, accessible and cheap way for all Canadians to lower the odds of becoming a cancer statistic.   

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© The Gazette (Montreal) 2008