HoldsUp

FoundMyFitness · 2025-03-05 · Rhonda Patrick (host), Kerry Courneya

The Science of Exercise for Cancer | Kerry Courneya, PhD

63 research-tied claims examined: 1 contradicted 3 overstated 55 supported 4 unverified

3

Overstated

0:00:43Kerry Courneyaoverstatedlow

Cancer patients who exercise while undergoing chemoradiation therapy are more likely to achieve a complete pathological response prior to surgery.

"And what we found is the patients who exercise while getting this chemoradiation therapy were more likely to have a complete response, meaning the tumors were completely gone prior to having the surgery." (said at 0:00:43)

A Phase II randomized controlled trial in 36 patients with rectal cancer receiving neoadjuvant chemoradiation (the EXERT trial) found that patients assigned to an exercise program had a significantly higher rate of complete or near-complete pathological response compared to usual care (56% vs 18%, p = 0.020). Observational cohort data also associate moderate-to-vigorous physical activity with increased tumor downstaging. However, claiming broadly that exercising cancer patients achieve higher complete response rates overstates the current body of evidence, which is derived from preliminary Phase II trial data and observational studies specifically in rectal cancer; larger Phase III trials are required to establish efficacy.

0:21:26Kerry Courneyaoverstatedlow

Low skeletal muscle mass in cancer patients is a critical driver of cancer recurrence and mortality.

"But now there's a lot of research showing that low muscle mass is really the critical thing driving risk of recurrence and death from cancer. So these patients who have low muscle mass or lose muscle mass when they're going through these difficult treatments tend to have the worst outcomes." (said at 0:21:26)

Low skeletal muscle mass (sarcopenia) and muscle wasting during cancer treatment are well-documented prognostic markers associated with poorer clinical outcomes, including reduced overall survival and recurrence-free survival across multiple solid tumors. An umbrella review of 59 meta-analyses encompassing 12 cancer types demonstrated that sarcopenia was associated with worse overall survival (HR = 1.59) and disease-free survival (HR = 1.64) in surgical patients, as well as poorer overall survival (HR = 1.49) in non-surgical therapy. Muscle wasting during neoadjuvant therapy is similarly associated with shorter overall and recurrence-free survival. However, asserting that low muscle mass is 'really the critical thing driving' cancer recurrence and mortality overstates the evidence: the literature comprises observational cohort studies showing associations rather than established causal dominance, the certainty of evidence remains low to very low across most outcomes due to observational confounding by disease stage and cancer cachexia, and the association is not universal across all cancer types (e.g., meta-analyses in breast cancer have found no significant association with recurrence or survival).

1:22:15Rhonda Patrick (host)overstatedmoderate

Randomized controlled trials and meta-analyses show that exercise is as effective as, or more effective than, SSRIs for treating major depressive disorder.

"There's been some pretty large randomized controlled trials over the years and even meta-analyses of these randomized controlled trials comparing exercise, whether it is aerobic, a lot of times running or cycling, um even resistance training has been thrown into the mix, uh comparing them to standard of care treatments for major depressive disorder like SSRIs, right? And exercise as a treatment, it seems to work just as good if not better than a lot of these SSRI drugs are working for the treatment of depression" (said at 1:22:15)

Systematic reviews and network meta-analyses comparing exercise to antidepressants (including SSRIs) generally find comparable effectiveness for symptom reduction in mild-to-moderate and non-severe depression, but do not demonstrate that exercise is more effective than antidepressants. In a 2022 network meta-analysis of 21 RCTs (n=2,551), exercise and antidepressants showed no statistically significant difference in depressive symptom reduction (SMD -0.12, 95% CI -0.33 to 0.10), while exercise interventions had higher dropout rates than pharmacotherapy (RR 1.31, 95% CI 1.09 to 1.57). Stating that exercise works 'better than' SSRIs for major depressive disorder is an overstatement of the comparative trial evidence.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.