It's not their sex, but their size and weight, which explain why men and women sweat differently. Scientists have found that larger individuals sweat more than smaller ones during exercise, showing that gender differences in sweating depend on morphology rather than gender.

Sweating and increasing circulation to the skin's surface are the two main ways that the body has to cool down. However, physiologists still don't completely understand how and why gender affects the sweating process.

There have been a number of studies dealing with gender-related differences in sweating, showing for example that fit men are more "efficient" at sweating - they sweat more than fit women during intense exercise.

The study now published in Experimental Physiology suggests that the most important differences between men and women are actually explained by variations in the ratio between body surface area and mass, and not by their sex.

The scientists recruited 36 men and 24 women for two trials involving rest and cycling, one at light and the other at moderate intensity, both conducted in an environment at 28 degrees Celsius and 36% humidity.

They measured their skin blood flow and sweating response, the two processes which help mitigate additional heat produced when exercising and keep body temperature under check.

The researchers found that regardless of sex, similar changes in body temperatures were observed. Weight and morphology explained 10 to 48 per cent of the individual variance in sweating and blood flow responses. In contrast, gender explained only five per cent of inter-individual variability in sweating.

Another finding of the study was that smaller men and women who have more surface area per kilogram of body mass were more dependent on increasing blood circulation and less dependent on sweating to reduce their body temperature.

The scientists concluded that the reason men and women may differ when it comes to cooling their body down during exercise is based on their morphology, not on their gender. Fit men may sweat more than fit women, but it is differences in morphology that mediate this difference.