Following up on last week’s exercise post, I wanted to focus on two recent studies that really drive home the benefits of physical activity for breast cancer survivors. If you’re not exercising now, here’s why you should consider it.
In 2017, Hamer and Warner published a review in the Canadian Medical Association Journal (Open Access link here). They analyzed 67 existing studies in an effort to ascertain what lifestyle factors were most important in reducing the risk of breast cancer recurrence in survivors.
The results were striking: of all the lifestyle variables that the researchers looked at, exercise came out on top. They found that engaging in moderate exercise resulted in a 40% decrease in cancer recurrence. This included easily-adoptable, low-cost programs such as brisk walking.
I want to stress: they weren’t talking about doing crazy-high amounts of exercise, but simply adhering to the current physical activity recommendations for US adults, which are as follows (summarized by the American Heart Association and taken from their website):
- Get at least 150 minutes per week of moderate-intensity aerobic activity or 75 minutes per week of vigorous aerobic activity, or a combination of both, preferably spread throughout the week.
- Add moderate- to high-intensity muscle-strengthening activity (such as resistance or weights) on at least 2 days per week.
- Spend less time sitting. Even light-intensity activity can offset some of the risks of being sedentary.
- Gain even more benefits by being active at least 300 minutes (5 hours) per week.
- Increase amount and intensity gradually over time.
Sadly, only 13% of recent breast cancer survivors actually met those exercise guidelines, and that number dropped even more as time went on. Consider how that affects overall cancer rates, when we talk about our chances as survivors: if the vast majority of the population is not engaging in a beneficial habit, the reported recurrence rates will reflect that. However, if you do incorporate exercise into your life, one could argue that your chances of recurrence are significantly improved over the numbers usually cited.
In addition, an increase of at least 10% of body weight after breast cancer diagnosis, which unfortunately happens often, increased both risk of recurrence and mortality. Again, patients who exercised were able to avoid this weight gain, improving their chances for disease free survival.
Nonetheless, while it seemed relatively straightforward to achieve the percent reduction in recurrence, the researchers stressed two very important points: (1) this reduction came after finishing treatments, not in lieu of them, so one should not assume that exercise would necessarily take the place of conventional cancer treatments, and (2) sadly, some cancers will recur even if the survivor is doing everything “right” and so if there is a recurrence, it should not be taken as the individual not doing enough. That’s the cruel unfairness of cancer.
The second study was original research with high-risk breast cancer patients by Cannioto et al. (2020), published in the Journal of the National Cancer Institute (Open Access link here). The study participants filled out a questionnaire about their exercise habits at four time points: (1) when they enrolled in the study after diagnosis (this question asked about pre-diagnosis exercise habits), (2) during chemotherapy, (3) one year after finishing treatment, and (4) two years after finishing treatment.
Once again, exercise was shown as having a significant impact: women who met the guidelines for physical activity (150 minutes/week of moderate exercise) before, during and after treatment had a 55% lower risk of recurrence and 68% lower risk of dying than those who didn’t meet the guidelines.
Even those who only started exercising after finishing treatment still had a significantly reduced risk of both recurrence and death compared to those who didn’t exercise at all. Additionally, benefits were also seen for those who consistently exercised, even if they didn’t fully meet the guidelines. So it seems that any exercise that these high-risk cancer survivors did was still better than not doing anything at all.
The same holds for you!
Both of these studies convey the importance of engaging in physical activity. Exercise is critical for the well-being of all humans, but even more so for breast cancer survivors. Think: when we receive a cancer diagnosis, we are ready to undergo potentially dangerous treatments, risking debilitating side effects that leave us bald, exhausted and wretched.
So why not engage in something as beneficial for body and spirit as moderate physical activity to help prevent the possibility of having to repeat the cancer treatment again?
A few more bits of information:
The easy-to-read executive summary of the US Physical Activity Guidelines for Americans can be found here.
For a plain-language synopsis of the Hamer and Warner (2017) review, see this Healio interview with co-author Dr. Ellen Warner.
For a plain-language synopsis of the Cannioto et al. (2020) paper, see this article in breastcancer.org.
Keep in mind that terms such as “moderate” and “intense” are relative to YOU. someone just starting out is not going to be able to handle the same level of intensity as a highly-trained individual, and there’s nothing wrong with that. Start where you are–it’s okay.
Finally, Dr. Robert Sallis, chairman of the American College of Sports Medicine’s Exercise Is Medicine inititative, has said, “If we had a pill that conferred the proven health benefits of exercise, physicians would prescribe it to every patient and healthcare systems would find a way to make sure every patient had access to this wonder drug.”
The two studies here show exactly why!
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