A new study by researchers from the University of British Columbia and the University of Colorado has found that weight-lifting may benefit appetite regulation and energy balance in breast cancer survivors.
The study, published in Appetite, involved 16 women who had completed treatment for hormone receptor-positive breast cancer within the past five years. On separate days, the women performed a single bout of resistance exercise, such as lifting weights, or sat quietly. The researchers measured their appetite sensations, appetite-related hormones and energy intake before and after each session.
The results showed that resistance exercise temporarily reduced hunger-inducing hormones and increased appetite-suppressing hormones compared to the sedentary condition.
Dr. Sarah Purcell, the study’s lead author and an investigator with the Centre for Chronic Disease Prevention and Management based at UBCO, said the findings suggest resistance exercise may help breast cancer survivors maintain healthy body weight and prevent obesity-related complications.
“Breast cancer survivors are often at increased risk of obesity,” she says. “We know that exercise can suppress appetite in people without previous cancer, at least in the short term, so we tested that in women with previous breast cancer who have low estrogen as part of their treatment. After a single bout of resistance exercise, we found some modest suggestions that exercise changes hormones to promote fullness and decrease hunger.”
About 80 per cent of people with breast cancer have estrogen receptor-positive cancer (ER-positive), and the standard of care after radiation or chemotherapy is five to 10 years of estrogen suppression.
Popular culture may portray cancer survivors as emaciated and lethargic, but weight gain—especially for women fighting breast cancer—can be as much of a worry.
“We think from experimental studies that estrogen is essential for appetite regulation and energy metabolism,” Purcell says.
Other studies have suggested that people with long-term estrogen suppression may increase their fat mass over the long term and decrease their muscle mass.
“We’re not sure what causes that. We also know that exercise can positively impact appetite in people without previous cancer, decreasing hunger or increasing satiety in certain conditions.”
Purcell said more research is needed to confirm the long-term effects of resistance exercise on breast cancer survivors’ appetite and energy intake and identify the optimal frequency, intensity and duration of activity for this group.
“It’s preliminary. People may not realize that exercise can promote appetite hormones in a way that would, at least theoretically, decrease later energy intake. We saw that a single bout of resistance exercise led to lower amounts of a hormone that promotes hunger—ghrelin—and higher amounts of a hormone that promotes satiety or fullness—peptide-yy.
“Again, the changes were modest, so we need to compare it to people without cancer, which we’re doing now.”
The National Institutes of Health supported the research, which appears in the latest issue of Appetite.