It's an intriguing question, especially when one considers that most exercise physiology experiments in the past have almost exclusively used male subjects. Adrienne Brown, a USC doctoral student in exercise science, hopes to shed more light on possible gender differences in exercise.

"Our pilot data from animal models suggests that females have lower mortality and morbidity rates when infected following fatiguing exercise," Brown said. "We think it might be because they have a better inflammatory response, which helps fight off opportunistic germs."

Brown's research, funded by the American College of Sports Medicine, is part of a large body of experiments in labs across the country that is examining gender differences in everything from pharmaceuticals to physiological activity. It's too soon to extrapolate her preliminary findings to human populations, but, at the least, Brown's study suggests a need for more research aimed at determining gender-related differences in exercise physiology.

In her experiments, Brown is measuring the effects of a common cold virus on laboratory mice that undergo rigorous exercise. As a group, the female mice have fared better than their male counterparts, both in warding off and recovering from illness after exercise.

The females also exhibit increased symptoms of infection—possibly due to their greater inflammatory response—which might lower their mortality rates, but might also be related to increased risk of arthritis and other inflammatory diseases.

"We have to start with animal models to understand what's going on, then eventually look at humans in this kind of research," Brown said. "It's interesting to consider because so many experiments in the past either relied solely on male subjects or didn't distinguish the differences between male and female subjects."

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