There’s always one of them. The person who has kept up with your fast pace on the trail run but looks like they’ve just stepped out of a shampoo advert, while you’re dripping sweat from your face in buckets. Or, the person working out next to you, who has pushed their heart rate way above 160bpm, but is still only glowing.

To get to the bottom of this (messy) issue, we first need to figure out why some people sweat more than others. There’s of course a point to sweating. When your body temp rises, your glands secrete sweat, and the evaporation of moisture from your skin helps you cool off. In the same way that some people are born with more hair follicles than others, you could be blessed with anything between 2 million and 4 million sweat glands at birth. The number will predict how much you sweat. We tend to think that men sweat more than women, but women generally have more sweat glands than men. So, what’s up?

Researchers from the University of Wollongong in Australia and Mie Prefectural College of Nursing in Japan have shown that sweating may have much more to do with body size than it does with what bits you were born with. The bigger (or fatter) you are, the more you’ll sweat because your body will generate more heat. Men tend to be bigger than women generally, so that explains that.

But there’s more to it… Other studies show that women need to push harder than men before they get all drippy and suggest women have a lower maximal sweat rate during exercise. Plus the fitter you are, the more you will sweat. Experts explain that as your fitness level improves, your body’s heat-regulating system kicks in sooner, cooling you down faster and allowing you to work harder, which translates to a lot more sweat.

So there’s your answer. While the amount you sweat doesn’t show you’ve had a good workout – it does show you’ve been exercising consistently and building your fitness. Give yourself a high five before you hit the shower!