There are many factors that determine how much one individual sweats, and, like any other human trait, there are some people that simply sweat more than others. On average, men tend to sweat more than women. Scientists figured this out by putting a similar group of fit men and women on a stationary bike for the same amount of time and effort. The researchers measured the number of sweat glands that were active and how much sweat each person produced. In the end, the fit men sweat more than the fit women not because they had more active sweat glands at any given time, but simply because their sweat glands produced more sweat. On that note, the number of sweat glands any one person has can range from two million to four million, and researchers have found that those who are deemed "heavy sweaters" more sweat glands than average and ones that are more sensitive to nerve stimuli.