Testosterone May Not Deliver Victory for Athletes, Study Found

Higher levels of testosterone during competition do not improve athletes' chances of victory, a new study finds.

"Many people in the scientific literature and in popular culture link testosterone increases to winning," Kathleen Casto, a graduate student in psychology at Emory University in Atlanta, said in a university news release.

"In this study, however, we found an increase in testosterone during a race regardless of the athletes' finish time. In fact, one of the runners with the highest increases in testosterone finished with one of the slowest times," she said.

Casto and colleagues measured testosterone levels in the saliva of varsity men and women cross-country runners before a race, after they warmed up and at the end of the race. They also checked levels of cortisol, a hormone related to stress.

Testosterone levels increased during warm-up, but cortisol levels did not. As expected, the runners had higher levels of testosterone and cortisol during the race. However, neither hormone was related to finish time.

"It's surprising that not only does competition itself, irrespective of outcome, substantially increase testosterone, but also that testosterone begins to increase before the competition even begins, long before status of winner or loser are determined," Casto said.

The study was published recently in the International Journal of Exercise Science.

Previous research has linked higher day-to-day levels of testosterone with long-term strength and power, including higher positions of authority in business.

"Although short-term surges of testosterone in competition have been associated with winning, they may instead be indicators of a psychological strength for competition, the drive to win," Casto said.

More information

The U.S. National Heart, Lung, and Blood Institute offers a guide to physical activity.