January 14, 2008
Derby players get game at higher hormone levels
By Andy Bennett
When David Edwards wanted to study the effects of competition on the hormone levels of roller derby players, he didn’t have far to go. The assistant varsity coach for Emory’s women’s swimming and diving team, Cindy Fontana, happens to moonlight as “InSINerator,” co-captain of the Toxic Shocks, one of four teams from Atlanta’s roller derby league, the Atlanta Rollergirls.
For Edwards, Charles Howard Candler Professor of Behavioral Neuroscience who is celebrating his 40th year at Emory, this is the latest of several research projects involving the relationships between hormones and behavior. Together with his collaborator Sarah Brown, an undergraduate from Princeton University, Edwards is measuring the effect team athletic competition has on women’s blood levels of testosterone and cortisol, two hormones associated with stress and competition.
During an Atlanta Rollergirls bout last July between the Toxic Shocks and 2006 league champions, the Sake Tuyas, Fontana and each of her 16 teammates were asked to provide saliva samples before and after their pre-game warm-up, and at various times throughout the bout. “It was a real treat to be rink-side with the Shocks,” Edwards recalls. “This is a bruising, contact sport and the skaters are amazing athletes.”
Cortisol, a well-known stress hormone, is secreted in the blood in response to stress or moderate exercise and plays a role in maintaining blood glucose and blood pressure.
Testosterone levels, on the other hand, increase in response to competition. Women who are not competing, but watching a game from the sidelines, show no elevation in testosterone levels. The precise physiological benefits this increase in testosterone levels has on competition are not fully understood, but links between high testosterone levels and dominance-related behaviors have long been speculated, and laboratory tests have indicated raised testosterone levels can improve women’s visuospatial performance.
Edwards has previously found cortisol and testosterone levels increase as a result of competitive play in Emory’s women’s soccer, volleyball and softball teams.
In studying roller derby, Edwards can see if the same trends he finds in college-aged women athletes in traditional sports hold true in a less traditional, competitive arena. As roller derby players tend to be in their 20s and 30s, he can now compare the results in older women as well.
In a summary of their findings, Edwards and Brown show cortisol levels climb steadily and peak toward the end of the three 20-minute periods, nearly tripling pre-game levels, and testosterone similarly raised an average of 60 percent, which is in accordance with previous findings of college-aged women in more traditional sports.
“The warm-up itself causes a significant increase in testosterone. So even before the start of competition, testosterone is going up in ways that perhaps are competitively beneficial,” Edwards reports.
Testosterone levels do not rise during ordinary workouts and practices. How non-athletic competition affects a woman’s testosterone levels is a question Edwards hopes to examine, as well as the effects of individual competition rather than as a member of team.
“From an evolutionary perspective, it seems likely that competitive team sports share elements with other group activities in which an increase in testosterone level may be important for reproductive survival,” he says. When was this selection likely to have occurred? “Long before the establishment of formal sporting contests.”