Given the stereotype of the “big swinging dick” on the trading floor, it should be no surprise that a study linking trading and testosterone has attracted attention. Researchers from Cambridge University studied 17 male traders at work and discovered that for each individual, temporarily higher testosterone levels seemed to be both cause and consequence of a profitable trading day.

Yet one can have too much of a good thing. On volatile days the traders are flooded with cortisol, a stress hormone, while too much testosterone turns calculated risk-taking into recklessness.