According to a systematic review and meta-analysis that included 42 studies and almost 47,000 patients, cancer patients with high levels of muscle strength and cardiorespiratory fitness (CRF) had a lower risk from death from any cause. This relationship held true even for patients with advanced-stage cancers. All-cause mortality decreased by as much as 46% for patients who were fit, when compared with patients who were weaker and had lower CRF.
The authors wrote: "Assessing physical fitness, particularly muscle strength and CRF, is crucial for predicting mortality in cancer patients. Implementing tailored exercise prescriptions to enhance these physical fitness components throughout the cancer continuum may contribute to reducing cancer-related mortality."[1]
An even larger systematic review and meta-analysis included 12 studies with 1.3 million cancer patients and examined the relationship between muscle strength, CRF and cancer mortality. This review showed that muscle strengthening activities were associated with a 13% lower risk of mortality, and that mortality was even lower - 28% - when aerobic activity was included.
The authors wrote that this was likely based on several mechanisms:
Changes in body composition which lowered body fat. Excessive body fat is a risk factor for cancer.
Higher body fat also contributes to insulin resistance, which in turn leads to higher levels of insulin-like growth factor (IGF-1). Insulin and IGF-1 can increase cell proliferation and reduce cellular apoptosis.
Weight loss: obesity is correlated with negative changes to the intestinal microbiome, which results in increased production of pro-inflammatory molecules and hormones including estrogen.
Strength training increases muscle mass, which improves glucose control and improves immune function.
Physical activity improves circulation which reduces hypoxic environments in which tumors can thrive.[2]
A large body of evidence from many sources supports exercise as an integral part of a strategy for surviving cancer. Kelly Turner is the author of Radical Remission : Surviving Cancer Against All Odds. The book resulted from her interviews with almost one thousand patients with advanced cancer who survived. While they collectively used dozens of strategies, they all used nine, which were described in detail in the book. She subsequently started the Radical Remission Project to train coaches, conduct research, and gather even more survival stories. After she and her team worked with cancer patients for a few years, she added exercise and movement as the tenth important strategy that increases survival.
Many cancer patients are unhealthy and lack fitness at the time of diagnosis. Instead of encouraging them to improve their health and become fit, oncologists often insist that diet has nothing to do with cancer risk or survival, and many discourage physical activity, instead advising patients to rest. Friends and family often agree.
This was the case for Ruth Heidrich, one of the reality patients who appeared in the hit film Forks Over Knives. Ruth was diagnosed with metastasized breast cancer in her 40s. She not only survived, but thrived thanks to adopting a plant-based diet as recommended by Dr. John McDougall, and vigorous exercise. She said in the film that her friends were telling her, "Ruth, you’re a cancer patient, you should be resting." She responded, "I just knew that if I built a strong body, I could beat this." And she did, going on to compete in triathlons and run marathons well into her 80s.
Pam Popper, President
Wellness Forum Health
[1] Bettariga F, Galvao D, Taaffe D et al. "Association of muscle strength and cardiorespiratory fitness with all-cause and cancer-specific mortality in patients diagnosed with cancer: a systematic review and meta-analysis." Br J Sports Med 2025 Jan; published online ahead of print
[2] Nascimento W, Ferrari G, Martins CB et al. "Muscle-strengthening activities and cancer incidence and mortality: a systematic review and meta-analysis of observational studies." Int J Behav Nutr Phys Act 2021 May;18:69
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