Dr. Rachel Perry, an associate professor at the Yale School of Medicine, has uncovered important findings on the effects of exercise for cancer patients.

Perry's newest study, published in the Proceedings of the National Academy of Sciences, explores the question: Why does exercise seem to protect people against cancer? In the study, Perry's team used metabolic tracers in mouse models of breast cancer and melanoma to learn how glucose — a nutrient that tumors use to fuel rapid cell division — is distributed when the body is active. They found that working muscles effectively outcompete tumors for glucose, causing tumors to receive less of the fuel they need to grow.

"Our goal ultimately is to develop insights that may lead to the development of an exercise pill — a way that people can get some of the beneficial effects of exercise without actually having to do that exercise. We know that when people are sick, when they have cancer, when they have other medical conditions, often it's very difficult, if not impossible, to exercise," Perry said.

The study focused on breast cancer and melanoma and found that fitness before cancer was protective. Even a small amount of exercise can help. Perry hopes her work will pave the way for more studies in people.