New findings from UBC Okanagan highlight a surprising benefit of exercise for breast cancer survivors
New research from the University of British Columbia (UBC) Okanagan adds a new dimension to how exercise benefits women who have survived breast cancer. While improving strength and cardiovascular endurance is well established, Dr. Sarah Purcell and her team report that physical activity may also influence weight management for survivors undergoing estrogen-blocking therapy, a common long-term treatment.
Why weight management matters for survivors on endocrine therapy
Breast cancer survivors generally enjoy favorable survival rates, but many face a higher risk of weight gain. Dr. Purcell notes that this gain can lead to obesity and increase the risk of heart disease and diabetes, as well as potentially affecting cancer recurrence. The exact reasons behind treatment-related weight gain remain complex and not fully understood, but a reduced exposure to estrogen during endocrine therapy is believed to play a role.
Obesity in this population is of particular concern because it may contribute to poorer health outcomes and complicate long-term survivorship. Accordingly, clinicians and researchers are eager to identify strategies that help manage body weight without compromising cancer treatment.
The study: exercise, appetite, and appetite-regulating hormones
Purcell and colleagues published their findings in Nutrition and Cancer. The study examined whether endurance and resistance exercise could influence weight trajectories among breast cancer survivors who are undergoing prolonged estrogen-blocking therapy. The research drew on data from two randomized trials that included female survivors and adults with obesity or high body weight. Participants were premenopausal before their cancer diagnosis and were currently receiving endocrine therapy at the time of the study.
One surprising outcome emerged: exercise appeared to affect appetite regulation. Specifically, survivors on estrogen-blocking therapy showed higher levels of the appetite-suppressing hormone Peptide YY (PYY) after exercise compared with women without a history of cancer. This was notable because estrogen suppression is often linked to weight gain, yet the PYY response suggested a potential avenue for better appetite control in the context of ongoing treatment.
What the hormone findings could mean for weight management
Dr. Purcell described the results as unexpected and intriguing. The elevated post-exercise PYY levels imply that physical activity may trigger a longer-lasting appetite-suppressing effect in breast cancer survivors undergoing endocrine therapy. This indicates a possible novel interaction between exercise and estrogen suppression that has not been observed in healthy populations.
From a practical standpoint, these hormonal responses could translate into real-world benefits. Even if participants did not report feeling less hungry at that moment, their post-exercise hormonal milieu appeared to dampen appetite relative to their body size, leading to smaller subsequent food intake. In short, regular exercise might help survivors manage treatment-related weight changes by engaging the body’s natural appetite-control systems.
What this means for guidelines and survivors
The study reinforces existing guidelines that advocate aerobic activities and resistance or strength training as key components of survivorship care. For survivors with obesity or higher body weight, combining these exercise modalities can improve body composition and support heart and metabolic health—factors that contribute to overall well-being during and after cancer treatment.
Purcell emphasizes that more research is needed to fully understand the mechanisms at play and to translate these findings into tailored exercise prescriptions. Still, the results offer a hopeful signal that exercise serves not only to strengthen muscles and endurance but also to modulate appetite and weight through hormonal pathways in a way that may complement endocrine therapy.
Looking ahead
As researchers continue to unravel the links between exercise, hormones, and weight in breast cancer survivors, clinicians may increasingly consider personalized exercise plans as part of comprehensive survivorship care. For patients, the message is encouraging: staying active could help manage one of the most challenging side effects of long-term therapy, supporting healthier weight and, by extension, broader health outcomes.
