Outpacing cancer with exercise: An interview with U of T's Linda Trinh

The American College of Sports Medicine, the American Cancer Society and 15 other international organizations recently issued new exercise guidelines that focus on how exercise affects cancer outcomes. The key message: Even a little exercise may help people avoid and survive many types of cancer. 

Linda Trinh, an assistant professor at the University of Toronto’s Faculty of Kinesiology & Physical Education, spoke to Jelena Damjanovic about the new guidelines. Trinh specializes in exercise and cancer survivorship.

We know that cancer treatments, while often effective, can leave people feeling ill, anxious, exhausted and frail. How can exercise help?

The evidence supporting the use of exercise for cancer prevention and survivorship has grown tremendously in the past decade. Exercise is beneficial at all phases of the cancer care trajectory, including prevention, treatment, recovery and improved survival. There is strong evidence that exercising during and after cancer treatment improves fatigue, anxiety, depression, physical function, and quality of life, and does not exacerbate lymphedema, a swelling of the arms or legs most commonly caused by the removal or damage to lymph nodes as part of cancer treatment.

Exercise is a safe and helpful way for individuals living with and beyond cancer to lessen the impact of cancer treatment on their physical and mental health. Cancer survivors should be moving throughout their cancer therapy and survivorship as tolerated. 

Can exercise change the trajectory of cancer once it begins?

In addition to addressing a number of cancer-related health outcomes, exercise can prevent recurrence and improve survival outcomes. In terms of prevention, there is now strong evidence that physical activity lowers risk of seven types of cancer, including colon, breast, kidney, endometrium, bladder, stomach cancer and esophageal adenocarcinoma. 

After a cancer diagnosis, exercise is associated with improved survival outcomes in patients with breast, colon and prostate cancer. Specifically, post-diagnosis physical activity seems to have a greater effect on cancer outcomes compared with pre-diagnosis physical activity.

What stands in the way of more people with cancer exercising? 

The barriers to physical activity participation are multi-faceted. Research shows that the most common barriers include lack of time, fatigue, treatment-related side effects and knowledge regarding exercise and its benefits during cancer treatment. This highlights a gap in what we know in research and how we can integrate exercise into the standard of care for cancer.

Part of the new guidelines suggest a ‘call to action’ for oncology clinicians to assess, advise and refer patients to appropriate exercise programs – clinical, community or self-directed. 

What are some tried and tested methods of motivating cancer patients to exercise?

Research has employed a variety of methods to motivate cancer patients to exercise – highly supervised exercise programs, home-based programs, a combination of supervised and home-based programs, community-based physical activity programming, hospital-based physical activity programs, print-based physical activity materials, oncologist referrals to exercise, [as well as] technology-delivered physical activity programming such as tailored websites, apps and activity trackers. 

We know that when cancer survivors adopt an exercise program, they can achieve long-term health benefits, but that only happens when exercise is maintained. As a behavioural researcher in exercise psychology, my research focuses on how we can design interventions that promote regular physical activity in cancer survivors. In addition to providing an exercise prescription tailored to the needs and preferences of the individual, it is important to incorporate behaviour-change strategies needed for maintenance. We set the cancer survivor up for success, which includes identifying the survivors’ personal benefits for participating in exercise, how to anticipate and overcome barriers to exercise, creating concrete action plans for exercise, how to self-monitor exercise, and goal setting as examples. We work with cancer survivors to make exercise a part of their regular lifestyle. 

According to the new guidelines, how much and what types of exercise may be the most needed, helpful and tolerable for anyone facing a cancer diagnosis?

Experts now recommend that cancer patients and survivors perform aerobic and resistance training for approximately 30 minutes per session, three times a week, to achieve health benefits. 

Examples of moderate activity exercise include brisk walking, light biking, water exercise and dancing. You can exercise for any length of time to build up to 30 minutes a day. For strength training, you can lift dumbbells, use elastic bands, or do body weight exercises such as chair sit-to-stands to build strength. 

How are these recommendations different from the recommendations on exercise and cancer first published by the American College of Sports Medicine in 2010?

In the past, the precise type and amount of exercise to treat the many different cancer treatment related health outcomes were not clear. In the absence of this information, cancer survivors were recommended to achieve the general public health guidelines of 150 minutes of moderate-to-vigorous physical activity.

Over time it was acknowledged that these guidelines were unachievable for cancer survivors with physical limitations. It was recognized that benefits may come from less exercise and experts in the field set out to develop more refined exercise prescriptions for distinct cancer-related health outcomes resulting in the updated guidelines.