Exercise — A Powerful Ally for Breast Cancer Survivors

Analysis by Dr. Joseph Mercola Fact Checked

exercise vital for cancer care

Story at-a-glance -

  • Studies show exercising regularly during chemotherapy and radiation treatments doubles your chance of surviving cancer
  • The benefits of exercising during cancer treatment include increasing your energy, minimizing drug side effects, reducing your risk of death and preventing a recurrence
  • Chemotherapy and radiation are more effective when you exercise because aerobic exercise brings oxygen-rich blood to your tissues and makes cancer tumors more receptive to treatment

According to Breastcancer.org,1 nearly 1 in 8 American women is at risk of developing breast cancer. Beyond skin cancer — which officials believe is the most commonly diagnosed cancer, even though the CDC and National Cancer Institute do not report or track2 certain types of skin cancer — breast cancer is the most commonly diagnosed cancer among women.

As of January 2019 more than 3.1 million women are either currently being treated for breast cancer or have previously completed treatment.

Those affected may be your mother, wife, sister or friend. Lest you think only women are affected, a man's lifetime risk of breast cancer is about 1 in 833, and nearly 2,670 new cases of male breast cancer were expected to have been diagnosed in the U.S. by the end 2019; of that number, the American Cancer Society says 500 will die.3

For certain, breast cancer is a devastating disease that robs you of your physical health and vitality. Along with the intense physical challenges, breast cancer also deals heavy emotional blows. About 30 years ago, I first became aware of the benefits of exercise related to cancer — suspecting exercise decreased insulin resistance, thereby helping the body more effectively fight the disease.

Now, given what I have learned about the positive effects of healthy fats and nutritional ketosis, detailed in my book, "Fat for Fuel," I realize exercise also signals PGC 1-alpha, a primary cue your body needs to reproduce and multiply your mitochondria.

As I explain in the book, because mitochondrial dysfunction seems to be at the core of most cancers, including breast cancer, activities like exercise that support mitochondrial biogenesis will strengthen your body and help it fight back.

How Cancer Takes a Toll on Your Body

If you or someone you know has breast cancer, without a doubt, you know the disease takes quite a physical toll. Cancer often shortens lifespans and negatively impacts overall quality of life.

Should you undergo conventional treatment for breast cancer, you can expect some or all of the following to become part of your life. While a number of these changes may only be temporary, in some cases, they are permanent.

Anxiety and/or depression

Diminished sex life and/or fertility difficulties

Peripheral neuropathy

Bone thinning and joint problems

Early menopause or increased menopausal symptoms

Reductions in physical fitness

Breast and arm changes

Fatigue and tiredness

Hair loss

Concentration and memory problems

Heart and lung issues

Weight gain or loss

Among the worst of cancer's effects relates to the damage it causes to your cardiovascular system and skeletal muscle. These effects arise from the combination of surgery, radiation and chemotherapy most often used to treat the disease.

In combination, that damage may lead to a dramatic decrease not only in your capacity to exercise, but also in your ability to perform day-to-day activities.

As part of his work at New York City's Memorial Sloan Kettering Cancer Center, Lee Jones, Ph.D., exercise scientist and director of the cardio-oncology research program, develops strategies to lessen the short- and long-term cardiovascular side effects of cancer treatment. He states:4

"What we've learned is cancer therapy leads to a dramatic reduction in a patient's cardiovascular reserve capacity — commonly known as your fitness level — and it appears to stay impaired even years after therapy.

In fact, we've found even a short course of chemotherapy has the same impact on the cardiovascular system as 10 years of normal aging. That's not good at all! But the good news is, in our clinical trials, we're discovering these effects can be attenuated in individuals who participate in structured-exercise training prescriptions."

Click here to learn moreClick here to learn more

Exercise Now a Vital Aspect of Standard Cancer Care

For years exercise has been one of the most frequently promoted methods for the prevention of disease. As you know, it's quite common for primary care physicians to suggest changes in your lifestyle if you are at risk for, or already struggling with, one of the commonly occurring chronic diseases such as diabetes or heart disease.

In the face of those diseases, very often your doctor will suggest you change your diet, stop drinking or smoking, lose weight or get more exercise.

According to Jones, although exercise has been routinely suggested for heart patients, for example, until recently, the importance of exercise as a means of preventing and treating any type of cancer was not widely recognized.

The prevailing belief was cancer patients would be too weak and frail to tolerate regular exercise. Now, Jones says, the views around exercise and cancer are changing for a number of reasons:5

"Perhaps the most important (reason) is the enormous progress we've made in cancer screening and prevention, as well as treatment. In combination, this now means people are living longer than ever after a cancer diagnosis and, accordingly, certain cancer diagnoses are no longer considered a death sentence.

Today, with nearly 14 million people in the U.S. living with a history of cancer, exercise has gained a lot of traction as part of the survivorship movement."

In more recent research published in the new journal JACC: CardiologyOncology, researchers found that if you're already exercising prior to a breast cancer diagnosis, you may help lower your risk for cardiovascular disease — the "leading cause of death in patients with primary breast cancer over 65 years of age."6,7

In an exciting development, another study found that exercise alters breast tumor gene expression, "suggesting that exercise may have a direct effect on breast cancer."8,9

Major Organizations Now Pair Exercise With Cancer Treatment

Similar to Memorial Sloan Kettering, Baltimore-based Johns Hopkins Medicine promotes exercise for patients undergoing cancer treatment, particularly due to its well-documented benefits. With respect to cancer, Johns Hopkins states exercise has been shown to:10

  • Boost overall physical and emotional well-being
  • Decrease sleep disturbances
  • Improve mood
  • Lessen treatment-related fatigue and nausea
  • Reduce the risk of breast cancer recurrence

In the short video presented above, Dr. Robert Thomas, consultant oncologist at two U.K. hospitals and clinical teacher at Cambridge University, discusses the importance of exercise during and after cancer.

In the U.K., Macmillan Cancer Support11 has also made strong arguments for the inclusion of exercise in standard cancer care. They recommend moderate-intensity exercise for 2.5 hours every week for anyone undergoing cancer treatment. Macmillan offers helpful information about the benefits of exercise for cancer patients on their website. Their YouTube channel12 also features several videos on the subject.

Oxygen-Rich Tissues Respond Better to Chemo and Radiation

Mark Dewhirst, Professor Emeritus of radiation oncology at Duke University School of Medicine, has spent years figuring out how to increase oxygen flow to tumors. His main objective for doing so relates to a desire to increase the effectiveness of chemotherapy and radiation drugs by promoting tissue oxygenation.

In a 2015 study,13 co-written by Dewhirst and published in the Journal of the National Cancer Institute, aerobic exercise was shown to not only slow breast cancer tumor growth in mice, but also to make the cancer more sensitive to chemotherapy. Said Dewhirst:14

"I have spent the better part of the last 30 years trying to figure out how to eliminate hypoxia in tumors, and have looked at a lot of different approaches — drugs, hyperthermia and metabolic manipulations. None has worked very well, and in some cases, made things worse. So these findings with exercise are quite encouraging."

After surgically implanting mouse breast cancer cells into female mice, Dewhirst and his team found the tumors to be slower growing in mice with access to an exercise wheel compared to mice without. Additionally, the density of small blood vessels feeding the tumors in the exercising mice was approximately 60 percent higher than that of the sedentary mice, making those tumors less hypoxic, or more oxygen-rich.

Because chemotherapy and radiation work better when oxygen is present, the results were significant. As such, study co-lead author Lee Jones validates exercise as a beneficial therapy for breast-cancer patients:15

"There is a growing body of work showing exercise is a safe and tolerable therapy associated with improvements in many outcomes such as fitness, quality of life and reductions in symptoms such as fatigue in a number of cancer types, including breast cancer. On the basis of these findings in mice, we are now designing studies to test whether exercise can inhibit tumor growth and risk of recurrence in humans."

Exercise Improves Your Chances of Surviving, Avoiding Cancer

A 2016 Australian documentary entitled "Exercise and Cancer," featuring research taking place at the Exercise Medicine Research Institute in Perth, suggests completing professionally prescribed exercise during chemotherapy and radiation treatments improves your chances of survival. Institute co-director Robert Newton states:16

"We now have a growing number of research studies showing if people hit a certain level of physical activity, which is relatively modest … they'll more than double their chances of surviving cancer."

A study17 published in JAMA found breast cancer patients who exercised moderately. For example, walking, for nine to 14.9 hours a week slashed their risk of dying from the cancer by 50%, compared to sedentary patients. In fact, any amount of weekly exercise increased, to some degree, a patient's chances of survival.18

When undertaken proactively, exercise can also help prevent cancer. This is done mainly by strengthening the body — through processes such as mitochondria reproduction and multiplication — and making it more resistant to disease. Says Jones:19

"For cancer, there's convincing evidence regular exercise is associated with a significant reduction in the risk of certain types, such as breast, colon and prostate cancer."

Tips for Sustaining Exercise During Cancer Treatment

Cancernet-UK offers the following tips to help you maintain a consistent exercise program during and after your cancer treatment:20

  • Establish an exercise routine — It's important to prioritize exercise as part of your daily schedule and establish a routine for it, using an exercise diary or fitness tracker to keep you focused
  • Increase exercise as part of your daily activities — Expanding physical activity in the context of your normal activities of daily living, such as taking the stairs or walking instead of driving for short errands, is an easy way to get more exercise
  • Avoid long periods of inactivity — If possible, get up from your workstation every 30 minutes and walk around for two minutes. Alternatively, use a stand-up desk, and/or take a longer walk during breaks or at lunchtime
  • Exercise as a social activity — Because many recreational activities and sports have a social aspect to them, by choosing one you enjoy and inviting family and friends to join you, you create a natural accountability system that will keep you exercising consistently

Important Cautions About Exercise and Cancer

If you're undergoing cancer treatment and are considering taking up exercise for the first time, it's advisable you consult with your oncologist first. You may also want to seek the advice of an exercise physiologist. Rather than a personal trainer, you will benefit more from working with an exercise physiologist who has experience tailoring exercise to the unique needs of cancer patients and survivors.

An exercise physiologist will know about cancer drugs and the types of treatment you are undergoing or have completed. As such, he or she will be able to customize an exercise program to your body's specific needs, with respect to your particular type of cancer.

If you have already been exercising regularly throughout your cancer treatment, be sure to allow appropriate recovery time in between workout sessions. Exercise causes damage to your muscles and adequate recovery is what actually provides the benefits. This is another reason why it would be worth your time and money to seek out professional help when designing a cancer-related exercise program.

Exercise to Reduce Your Risk of Cancer Recurrence

As mentioned, evidence supporting exercise as a means of reducing your risk of cancer recurrence is impressive. For example, previous research has shown breast and colon cancer patients who exercise regularly have up to half the recurrence rate of nonexercisers.21,22 According to Ciarán Devane, chief executive of Macmillan Cancer Support:23

"Cancer patients would be shocked if they knew just how much of a benefit physical activity could have on their recovery and long-term health, in some cases reducing their chances of having to go through the grueling ordeal of treatment all over again. It doesn't need to be anything too strenuous — doing the gardening, going for a brisk walk or a swim all count."

A 2015 meta-analysis24 of 22 previous research studies, involving 123,574 participants, found those who reported high lifetime prediagnosis physical activity had a significantly lower risk of death from breast cancer compared to those reporting low/no lifetime prediagnosis physical activity.

Additionally, both prediagnosis and post-diagnosis physical activity were associated with a reduced risk of breast cancer progression and recurrence. The study authors suggested, "[A]ppropriate physical activity may be an important intervention for reducing death and breast-cancer events among breast-cancer survivors."

Research published in the Canadian Medical Association Journal25 examined lifestyle factors influencing breast-cancer recurrence rates. The study involved a meta-analysis of 67 articles related to cancer recurrence as related to patient lifestyle choices such as diet, exercise and weight management. The study authors noted:26

"Of all lifestyle factors, physical activity has the most robust effect on breast-cancer outcomes. Weight gain of more than 10 percent of body weight after a breast-cancer diagnosis increases breast-cancer mortality and all-cause mortality."

Furthermore, the authors assert women who achieve 30 minutes of physical activity a day, five days a week, or 75 minutes of intense exercise once a week, significantly reduce their risk of breast cancer death and recurrence. In comparison, women who are overweight or obese seem to have the lowest chances of survival.

Dr. Ellen Warner, oncologist at Sunnybrook Health Sciences Center, professor of medicine at the University of Toronto and research co-author commented:27

"Exercise has the greatest benefit of lowering risk of recurrence and has many other secondary benefits like helping with weight management, which itself lowers the risk of recurrence, and fewer side effects from chemo, radiation and hormone therapy."

While exercising during breast cancer has proven benefits, clearly, your best bet for beating this disease is to proactively prevent it. In addition to regular exercise, adopting a ketogenic, or fat-burning, diet appears to be a promising cancer deterrent. Be sure to read my book, "Fat for Fuel," to learn more about safeguarding your life from serious illnesses like breast cancer.