Why Physical Activity Could Help Prevent Cancer

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Dr. Christine Friedenreich doesn’t write prescriptions but if she did, she’d probably tell you to take a hike. For real.

Barely able to contain her vast inventory of knowledge, and eager to share astonishing results, the renowned researcher can tell you multiple reasons why physical activity is good for you. The main benefit – the one she has devoted hundreds of thousands of hours to – is cancer prevention. “There have been nearly 100 studies done that look at physical activity and its effects on breast cancer,” says Friedenreich, scientific leader at Alberta Health Services and a professor at the University of Calgary. “They confirm a measurable 25 to 30 per cent decrease in risk when comparing people who are most active versus people who are less active.”

For nearly three decades, the prominent researcher has devoted herself to studies targeting cancer prevention. Her goal: to reduce the odds of people developing cancer by intervening early enough to change some of the modifiable risk factors that influence the onset or promotion of cancers. “There are so many risks we can’t control – genetics, environmental factors, aging. I’m studying modifiable lifestyle risk factors, things you can change – things you have control over,” says Friedenreich.

She first set out to dissect a critical piece of the cancer puzzle in 1986, by studying the relationship between smoking and cancer. That study, nearly 30 years ago, showed that even if you could reduce smoking prevalence rates by two to five per cent per year, you could increase life expectancy by up to two years. Next, Friedenreich went on to explore how diet, lifestyle and environmental factors impact risk of cancer and chronic disease, completing her post-doctoral fellowship at the International Agency for Research on Cancer (a division of the World Health Organization) based in Lyon, France. While in France, Friedenreich helped spearhead the European Prospective Investigation into Cancer and Nutrition (EPIC) study – a massive cohort study of 522,000 people across 10 European countries, which has resulted in hundreds of research papers that have demonstrated the role of diet, lifestyle and other factors in cancer causation.

After an exhilarating year abroad, Friedenreich and her husband landed in Calgary, where she met Kerry Courneya, an exercise psychologist who worked at the University of Calgary. “We started doing research together and quickly identified gaps in the literature on how physical activity is related to the risk of developing cancer, how it can be used to help people cope with cancer treatments, how it can help rehabilitate after cancer, and how it can improve the overall rate of survival,” says Friedenreich.

Motivated by compelling results which show that physical activity can have a profound effect on various types of cancers, Friedenreich and Courneya embarked on a mission to develop a set of guidelines indicating the precise dose, nature and timing of physical activity that offers optimum cancer fighting benefits. Furthermore, the pair set out to explore the measurable benefits of physical activity during cancer treatment, and its potential impact on cancer survival. Friedenreich first developed and published a questionnaire called the Lifetime Total Physical Activity Questionnaire – a tool the team could use in studies measuring the relationship between physical activity and cancers of the breast, prostate and endometrium (uterus). In their first case-control study of breast cancer, they studied women’s lifetime activity levels, and discovered that post-menopausal women who had a lifelong history of regular exercise had decreased rates of breast cancer of around 42 per cent. Alternatively, women who started exercising later in life (after the onset of menopause) had a surprisingly-similar decreased risk of 40 per cent. “These were really interesting results,” says Friedenreich. “The important message is, physical activity is incredibly beneficial to your health and it’s never too late to start.”

Next came the ALPHA Trial (Alberta Physical Activity and Breast Cancer Prevention Trial) that began in 2003, a study of 320 post-menopausal women that examined how a year-long exercise program could reduce breast cancer risk. The ALPHA Trial showed that aerobic exercise reduced many biomarkers associated with breast cancer risk. It also revealed that these biomarkers changed even more with higher levels of exercise.

Subsequently, her BETA trial (Breast Cancer and Exercise Trial in Alberta) in 2010, studied 400 women to explore how the amount, intensity and frequency of exercise impact cancer prevention. Partially-funded by the Alberta Cancer Foundation, the BETA Trial results are currently being analyzed and will enable Friedenreich and her team to devise public health guidelines outlining the optimum prescription of physical activity to aid in cancer prevention. “So far our results show that any amount of activity is better than none, but more intense activity more often is better,” says Friedenreich. Friedenreich and her team are now embarking on the final frontier of their research, with the AMBER study (Alberta Moving Beyond Breast Cancer). The study involves 1,500 newly-diagnosed breast cancer patients, and examines how physical activity and physical fitness influences survival after cancer. “All of these studies involve exercise, but we don’t like to use the word exercise because that can put people off. We prefer to call it physical activity – encompassing movement of any kind,” she says.

Friedenreich points out that on any given day, aside from eight hours of sleep, and potentially 30 minutes of exercise, people could find themselves sedentary for more than 15 hours. She has joined the call to action, advocating for an even or gradual shift from sedentary behaviour to light activity. “Get up and unload the dishwasher, go outside and do some gardening, have your meetings while walking,” she says. “Any kind of movement is better than none.” Friedenreich was the recipient of the 2013 O. Harold Warwick Prize. Named after a pioneering cancer researcher and presented by the Canadian Cancer Society, this prestigious award recognizes scientists who have made a major contribution to cancer control research.

Friedenreich is happy she chose to work in a field that has such immediate and direct applications, with benefits that have been so clearly documented across multiple diseases. She describes her work as empowering. “Cancer scares people; makes them feel like they’re losing control over their lives,” she says. “In my field we have the opportunity to give people back some measure of control; empower them to make choices that can make measurable differences in their lives.”


Why Physical Activity Could Help Prevent Cancer was written by Pat Fream, Communications Manager at Wellspring Calgary. Photo by Cooper & O’Hara.

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