Mara Rutherford presents her poster, “Effects of Caffeine and Menstrual Phase on Performance of Female Athletes during Heat Stress,” at Experimental Biology 2018. Credit: Nathalie Fuentes

Menstruation and its effect on athletic performance is not often discussed in athletics, even though most female athletes deal with it in their daily lives. However, more researchers have begun to look at this subject, and some are observing how other factors, such as caffeine consumption, could influence a female’s performance during sports.

A recent survey found that 61 percent of women are self-proclaimed coffee addicts. Previous research has shown that that caffeine stimulates the central nervous system to enhance endurance performance. In addition, many female athletes use birth control pills (oral contraceptives) to regulate their menstrual cycle; these pills may also enhance the effects of caffeine.

Maura M. Rutherford, a student in the department of human kinetics at Saint Francis Xavier University in Canada, and other scientists studied the potential impact of caffeine and hormonal changes across the menstrual cycle on women’s athletic performance. Six recreationally active women who were taking oral contraceptives volunteered for this study. They took a caffeine supplement and then ran 5 kilometers (3.1 miles) at different stages of their menstrual cycle. The investigators found that caffeine supplementation improved the athletes’ performance in the early follicular phase, when the follicles that will eventually release an egg during ovulation start to develop. However, caffeine did not improve the running time in the mid-follicular phase (i.e., ovulation) of the menstrual cycle. These results could be due to a sudden increase in fatigue that was observed in this phase.

Nathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

Nathalie served as a meeting blogger for Experimental Biology 2018.