Why Do I Sweat So Much When I Run?

Why Do I Sweat So Much When I Run?

The fact that you sweat is a good thing – if you didn’t, you’d probably have to roll around in mud just to cool off, the way pigs (who don’t have sweat glands) do.

But, ironically, sweating too much can make you feel like a pig. You might feel slimy, uncouth, and maybe a little as if there were something wrong with you. After all, the guy next to you just ran the same distance at the same pace as you. So why is he just glistening while you look like you just stepped out of a swimming pool?

In a situation like that, you might ask yourself, “Why do I sweat so much when I run?”

Read on to find out the answer.

Why Do We Sweat?

Most people know that we sweat in order to cool down.

We sweat during strenuous activity (like running) and even when going through emotional or mental stress. If we didn’t sweat in these situations, we’d overheat and overheating isn’t fun.

So whenever your body detects a rise in its core temperature, its sweat glands release, well, sweat onto the surface of your skin. This sweat doesn’t sit on your skin, however – it evaporates. And it’s this evaporation that causes a cooling effect, which lowers your core temperature.

But what is sweat?

Sweat is, to put it simply, a mixture of mostly water and salt. That means that when you sweat, you not only lose fluids, but you lose electrolytes (that’s the medical term for “salt”) as well. If you lose too much of each, you’ll experience some detrimental consequences like fatigue, dizziness, digestive issues, and even cramping.

That’s why it’s important that you hydrate properly. If you’re worried that you’re losing too many electrolytes, you can opt for electrolyte-rich energy drinks or for salt tablets.

Again, it’s absolutely vital to replenish the fluids you lose during running via sweat. Failure to do so can screw up your body’s ability to regulate its core temperature, which, as we’ve said, can cause a wide variety of awful things, including heatstroke.

Types of Sweat Glands

According to ScienceDirect, about 1.6 million to 5 million sweat glands are found on the human skin – how much a person has is dependent on individual differences.

What most people don’t know is that there are actually two different types of sweat glands.

The first type is called the “eccrine gland.” These are what most people think of when they think about exercise. They’re found throughout the body and secrete sweat directly on the surface of your skin, where it then evaporates.

The second type is called the “apocrine gland.” This type is the one that makes people feel like pigs. They’re found in the groin and armpit areas, where hair is generally heavily concentrated. These release sweat in times of anxiety or distress, and instead of evaporating (because, remember, the areas in which they’re found aren’t exposed to the open air), they mix with the bacteria on the skin. This causes body odor.

For information on the differences between the two glands, check out the extremely simple, easy-to-understand video below.

Why Do I Sweat So Much When I Run?

Now that you have a basic understanding of what sweat actually is and why it’s important, let’s get to the nitty-gritty.

Let’s talk about why you sweat so much when you run.

First of all, how much you sweat depends on various factors. These factors include your age, weight, level of fitness, the climate in which you live, and genes. Gender is a factor, too – men typically sweat more than women.

Obviously, the more body fat you have the more energy you’ll need to expend relative to your leaner peers to do the same activity. That means the fatter you are, the more you’ll sweat.

And if you live in a hot climate, then of course you’re likely to sweat more than someone who doesn’t. That’s obvious too.

But the counterintuitive thing is that a fitter person will begin to sweat much earlier and faster than a less fit person. This is because the human body is, in a lot of ways, a brilliant thing. Not only did it adapt to the necessity of running over millennia, but it also continues to adapt to your everyday habits. That is, if you run or exercise frequently, it prepares to cool down by activating your sweat glands before you’re even hot.

At the same time, the less fit person will probably end up sweating more than the fitter person because the less fit person has to expend a lot more energy to do the same task and thus end up with a higher core body temperature.

The bottom line is that sweating is a good thing and it’s hard to pinpoint how much is too much. But if you still feel that you’re sweating more than the average person (even after taking into consideration the factors above), then read on for what you can do to counteract the problem.

Excessive Sweating Causes

The following are some of the common causes of excessive sweating:

  • Hyperhidrosis. This is a medical condition that affects you even when you’re not running. If you find that your palms are so sweaty that you have difficulty doing normal tasks (like turning a doorknob, for example), then it’s likely that this is the culprit. If you sweat profusely even when performing sedentary tasks, then you should see a doctor. About 5% of the population suffers from this condition, so you’re not alone.
  • Drinking too much caffeine. Caffeine has been shown to increase perspiration – if you cut back on it, you might find that it solves your problem.
  • Alcohol. The same advice for caffeine applies here. Cut back on the alcohol and see if you sweat less
  • Smoking. Everyone knows the bad health effects of smoking, but it can also be affecting the rate at which you sweat. Cut it down (or better yet, kick the habit entirely).
  • Synthetic fabrics. If your work out attire consists of things made with synthetic fabrics, its possible that they’re trapping in too much heat, making you sweat more.

How to Stop Sweating So Much

And there you have it: now you know the answer to why you sweat so much when you run.

If you have any questions or concerns, make sure to leave them in the comments below.


  1. Popular Mechanics
  2. ScienceDirect