What the research tells us about exercise, recurrence and survival after cancer
Cancer treatment has traditionally been built around things done to the patient: surgery, radiation, chemotherapy, endocrine therapy, immunotherapy. Exercise is different. It is something the patient can do for themselves.
And increasingly, the research suggests that movement after a cancer diagnosis may be more than rehabilitation. It may be associated with a lower risk of recurrence and, even more consistently, with a lower risk of dying from cancer.
Many of the benefits appeared at roughly 7.5–15 MET-hours of activity per week – the equivalent of about 2½ to 4 hours of brisk walking spread throughout the week. MET-hours are a way of combining how hard you exercise × how long you exercise into one number.
A MET (metabolic equivalent of task) represents energy expenditure relative to rest:
- 1 MET = sitting quietly
- 3 METs = easy/moderate walking
- 4 METs = brisk walking
- 6 METs = moderate cycling or fairly vigorous activity
- 8–10 METs = jogging/running or vigorous singles tennis
That does not mean exercise replaces conventional cancer treatment. It means that once the surgery is finished, the radiation machine stops spinning, and the prescriptions have been filled, there may still be another piece of treatment hiding in plain sight: move your body.
The Breast Cancer Story
Some of the most compelling evidence comes from breast cancer.
One of the landmark studies was the 2005 JAMA paper “Physical Activity and Survival After Breast Cancer Diagnosis.” Researchers followed 2,987 women with stage I–III breast cancer in the Nurses’ Health Study. Compared with women exercising less than three MET-hours per week, women performing 9–14.9 MET-hours per week had about half the risk of dying from breast cancer. Interestingly, the association appeared particularly strong among women with estrogen- and progesterone-receptor-positive tumors.
And we’re not talking about training for a marathon. The authors estimated that the greatest apparent benefit occurred around the equivalent of walking three to five hours per week at an average pace.
More recent research has continued to examine the question. The systematic review “Postdiagnosis Recreational Physical Activity and Breast Cancer Prognosis: Global Cancer Update Programme (CUP Global) Systematic Literature Review and Meta-analysis” found that every additional 10 MET-hours per week of recreational activity was associated with about 15% lower all-cause mortality and 14% lower breast-cancer-specific mortality.
Recurrence itself is more complicated. Some studies and meta-analyses have found lower recurrence among active women, while the CUP analysis of six studies did not find a statistically significant association with recurrence. So it would be an overstatement to tell women that exercise has proven to prevent breast-cancer recurrence. The mortality evidence is considerably stronger.
Still, the overall picture is difficult to ignore.
It Isn’t Just Breast Cancer
Colorectal cancer provides another particularly interesting example.
The 2024 paper “Post-diagnosis Physical Activity and Sedentary Behaviour and Colorectal Cancer Prognosis: A Global Cancer Update Programme (CUP Global) Systematic Literature Review and Meta-analysis” evaluated 16 observational studies involving more than 82,000 patients. Physical activity was consistently associated with better outcomes, with estimated reductions ranging from 13% to 60% across recurrence and mortality outcomes. The expert panel characterized the evidence linking recreational physical activity with both all-cause mortality and cancer recurrence as “limited-suggestive”—promising, but not proof of causation.
Prostate cancer tells a similar story. A recent systematic review, “Post-diagnosis Physical Activity in Relation to Mortality Among Prostate Cancer Survivors: A Systematic Review and Meta-analysis,” examined more than 50,000 men. Men performing at least 7.5 MET-hours of physical activity per week had about a 31% lower rate of all-cause mortality than less-active men.
The message is beginning to look considerably larger than any one tumor.
Looking Across Cancer
Perhaps the most useful big-picture paper is “Physical Activity and Mortality in Cancer Survivors: A Systematic Review and Meta-analysis.”
Researchers reviewed 136 studies and found that higher levels of physical activity were associated with improved survival across multiple cancers. For cancers collectively, people reporting the highest levels of post-diagnosis activity had a 37% lower rate of cancer-specific mortality than those reporting the lowest levels. Favorable survival associations were identified for at least 11 different cancer sites.
A newer analysis makes the breadth of the association even more intriguing. “Leisure-time Physical Activity After Diagnosis and Survival by Cancer Type: A Pooled Analysis” examined 90,844 cancer survivors from six large American cohorts.
Compared with people doing no moderate-to-vigorous physical activity, those achieving approximately the recommended amount of exercise—7.5 to less than 15 MET-hours per week—had better overall survival after cancers of the breast, colon, rectum, prostate, lung, kidney, bladder, endometrium, oral cavity and other respiratory sites.
Another recent paper, “Exercise and Survival Benefit in Cancer Patients: Evidence From a Comprehensive Meta-analysis,” pooled 151 cohorts representing nearly 1.5 million cancer patients. Post-diagnosis physical activity was associated with lower cancer-specific mortality in breast, prostate, lung and colorectal cancers.
That is a remarkable amount of epidemiologic smoke. The remaining question is how much fire lies underneath it.
Why Would Exercise Affect Cancer?
There probably isn’t one mechanism. Cancer doesn’t work that way, and neither does exercise.
Regular physical activity improves insulin sensitivity and lowers chronic hyperinsulinemia. Insulin and insulin-like growth-factor signaling can promote cellular proliferation, making metabolic health particularly interesting in cancer biology.
Exercise also reduces visceral adipose tissue. Fat is not merely a storage locker for excess calories. It is metabolically and hormonally active tissue, producing inflammatory signaling molecules and, through aromatase activity, contributing to estrogen production. That provides an especially plausible connection with hormone-sensitive breast cancer.
Physical activity can also affect inflammatory signaling, immune function, skeletal muscle metabolism and circulating hormones. Researchers are investigating how these changes might influence the tumor microenvironment and the ability of microscopic residual cancer cells to survive and proliferate. A review appropriately titled “Epidemiology and Biology of Physical Activity and Cancer Recurrence” discusses many of these proposed pathways while emphasizing that the biology remains incompletely understood.
There is also a simpler explanation for some of the survival advantage: fit people tolerate illness better.
Cancer treatment can take a tremendous toll on muscle, cardiovascular capacity, glucose metabolism and functional independence. Maintaining muscle and aerobic capacity gives a patient more physiological reserve with which to tolerate surgery, chemotherapy, radiation and the years that follow.
Exercise may therefore influence cancer survival both directly and indirectly.
Association Is Not Causation
There is an elephant on the treadmill.
Most of the impressive survival numbers come from observational studies, not randomized trials assigning thousands of cancer patients to exercise or sedentary living for ten years.
People who exercise after cancer may eat differently. They may smoke less. They may have less advanced disease, maintain healthier body weight, adhere more consistently to treatment, have greater socioeconomic resources, or simply feel well enough to exercise because their cancer is less aggressive.
Researchers adjust statistically for many of these factors, but statistics cannot make every difference disappear.
This is why a hazard ratio of 0.60 should not be translated into the claim that exercise prevents 40% of cancer deaths. What we can say is that people who are physically active after cancer diagnosis repeatedly demonstrate better outcomes, and the association remains remarkably consistent across different populations and different cancers.
An umbrella review published recently examined 740 meta-analytic associations involving exercise and cancer survivorship. It found strong or highly suggestive evidence connecting post-diagnosis physical activity with lower all-cause mortality in breast and colorectal cancer, along with numerous improvements in fatigue, fitness, strength, mental health and quality of life.
In other words, even while we’re arguing about exactly how much exercise changes recurrence, we aren’t waiting to discover whether exercise is good for cancer survivors. It is.
How Much Does It Take?
The encouraging part is that the research doesn’t suggest everyone needs to become an athlete.
Many of the favorable associations appear around the familiar public-health target of approximately 150 minutes of moderate-intensity activity per week, or roughly 7.5–15 MET-hours per week. In the classic breast-cancer study, the equivalent of several hours of ordinary walking each week was associated with substantial benefit.
I would add resistance training whenever practical. Cancer treatment, aging, inactivity and hormonal therapies can all conspire to remove muscle and bone. Walking is wonderful, but skeletal muscle needs to be asked occasionally to lift something heavier than itself.
And exercise does not have to arrive in a matching outfit with a gym membership. Walk. Hike. Garden. Ride a bicycle. Swim. Dance. Play tennis. Lift weights. Climb stairs. Carry groceries. Take the dog farther than the mailbox.
The best exercise program is generally the one that actually happens.
For decades, cancer survivors were often told to rest. Rest certainly has its place during treatment. But prolonged inactivity extracts its own price.
We now have substantial evidence that movement improves strength, cardiovascular fitness, metabolic health, fatigue and quality of life after cancer. Beyond those established benefits lies an increasingly provocative observation: people who exercise after cancer diagnosis tend to live longer, and in some cancers they may also experience fewer recurrences.
Author
Scott Rollins, MD, is Board Certified with the American Board of Family Practice and the American Board of Anti-Aging and Regenerative Medicine. He specializes in bioidentical hormone replacement for men and women, thyroid and adrenal disorders, fibromyalgia and other complex medical conditions. He is founder and medical director of the Integrative Medicine Center of Western Colorado (www.imcwc.com) and Bellezza Laser Aesthetics (www.bellezzalaser.com). Call (970) 245-6911 for an appointment or more information.
Studies to link in the published article
- Physical Activity and Survival After Breast Cancer Diagnosis — Holmes MD et al., JAMA, 2005. PubMed
- Postdiagnosis Recreational Physical Activity and Breast Cancer Prognosis: Global Cancer Update Programme (CUP Global) Systematic Literature Review and Meta-analysis — International Journal of Cancer, 2023. PubMed
- Post-diagnosis Physical Activity and Sedentary Behaviour and Colorectal Cancer Prognosis: A Global Cancer Update Programme (CUP Global) Systematic Literature Review and Meta-analysis — International Journal of Cancer, 2024. PubMed
- Physical Activity and Mortality in Cancer Survivors: A Systematic Review and Meta-analysis — JNCI, 2020. PubMed
- Post-diagnosis Physical Activity in Relation to Mortality Among Prostate Cancer Survivors: A Systematic Review and Meta-analysis. Article/PubMed record
- Leisure-time Physical Activity After Diagnosis and Survival by Cancer Type: A Pooled Analysis — 2025. PubMed
- Exercise and Survival Benefit in Cancer Patients: Evidence From a Comprehensive Meta-analysis — 2025. PubMed
- Epidemiology and Biology of Physical Activity and Cancer Recurrence. PubMed
