Wet hands. There is nothing less attractive than shaking someone’s hand to find that it’s wet. It’s even worse if they’ve just come out of the toilet. And this is quite bizarre really; because it’s more likely a grown person would wash their hands after going to the bathroom and not dry them properly, than accidentally pee on themselves. But, either way it’s quite a different story when there is no toilet, or water of any kind around, and you’ve still got wet hands. Because in this case, it’s probably sweat.

 Getting sweaty palms on a regular basis is a condition called palmar hyperhidrosis, and it affects over 1 percent of the US population (that’s around 4 million people). While it might seem like a minor issue to most of us, Dr. Lewis P Stolman from New York University School of Medicine notes in his paper on the topic that sweat on hands may “soil paper and artwork and make it virtually impossible to play many musical instruments”. With flutes slipping and sliding out of the hands of potential virtuosos, we ought to found out why we get sweat on our hands.  

 Palmar hyperhidrosis is thought to be caused by an overworked sympathetic nervous system. The human body runs on two nervous systems: sympathetic, which is responsible for bodily functions that let you run quickly and fight dangers, and the parasympathetic system that allows your body to rest and digest. Usually these systems are in a friendly balance, enabling us to sleep when we need to, and run away from a Sabre tooth tiger when the situation arises. But if the balance is tipped toward the sympathetic nervous system, it can make us sweat unnecessarily, and in places that we don’t usually sweat in.

 So why do we need sweat anyway?

 Sweating allows the body to regulate its temperature. If we get too hot on the inside, it’s not only uncomfortable, but can mean that bodily functions don’t work as efficiently as they should. Millions of sweat glands are found in the human body, and surprisingly, more than half of these are in the hands. When our body heats up, through physical exertion for example, nerves activate sweat glands to make them open up and release sweat, which cools our body down.

 There are two situations that our nerves will stimulate sweat glands to make us release sweat: during physical heat, and emotional heat. When we are emotional our heart rate speeds up and body temperature rises in the same way that it does when we go for a run. So it’s no surprise that the body should need to release that heat during emotional times, just like it would when we are physically stressed.

 Emotionally induced sweating is generally restricted to palms, soles, and sometimes the forehead, but sweat from physical heat pretty much occurs everywhere. Unfortunately, we don’t actually know why emotional sweat is restricted to these areas of the body and why certain people are more susceptible to sweating in emotional times.

One theory says that everyone gets sweaty hands in emotional situations, but for severe sufferers of palmar hyperhidrosis the nervous system will activate sweat glands during only mildly emotional times. So for non-sufferers, it takes much more emotional strain to get the nerves moving to stimulate sweat. This would explain why anxiety and social stress are known to make the condition worse.

 Next time someone shakes your hand, and it feels a little moist, don’t judge (and don’t mention the flute).  Palmar hyperhidrosis is a serious medical condition that affects more than one in a hundred people. Although, come to think of it, since I don’t have the figures on the percentage of people who pee on themselves, it’s hard to say which would be more likely.