The odor of male sweat is said to contain pheromones to attract the opposite sex. We are not talking about days old sweat here men! Some years ago at a concert by Bon Jovi, when he ended the performance, he moved his head so energetically that all you could see was sweat flying off his head and upper body. Women were screaming with carnal instinct just looking at him men! So women find men look sexy while sweating so plentifully.
Androstadienone, a strong pheromone found in sweat was researched by a team at the University of California who found that this chemical found in male sweat causes a woman's hormone level and sexual arousal to increase exponentially. But don't ditch those antiperspirants men! Old sweat is definitely a BIG turn off.