How To Stay Safe Running In Humidity

Nobody prepares you for running in humidity. When I first started going on morning runs in Florida, I knew it would be hot, but I was not prepared for the level of humidity that I encountered. It was like running in a sauna; within seconds of stepping outside, I was drenched in sweat. I always ended up looking like I had just jumped into a pool fully clothed.

No matter you shake it, humidity has a large effect on your runs. Running in high humidity can be difficult and dangerous, but there are ways to make it easier and safer.

While humidity has a few different effects on runners, the most important thing is to stay hydrated. Drink plenty of water before, during, and after your run. Wear light, breathable fabrics that will help you stay cool and dry. And take it easy if you're not used to running in high humidity.

Many of us run to feel good or to improve our overall health. But feeling dehydrated because you lost all your water trough sweat on a run just won't make you feel good.

What Is Humidity?

Humidity is the amount of water vapor in the air. The higher the humidity, the more water vapor there is in the air. You can't really see it. But you sure can feel it!

There are a few different ways to measure humidity. The most common is relative humidity, which is a measure of how much water vapor is in the air compared to how much water vapor the air can hold. This is measured in a percentage and is the most common way we talk about humidity. It can be as high as 100% in places such as Florida, and as low as 0% in desert places like Nevada.

But another way to measure humidity is dew point. This is the temperature at which water vapor will condense out of the air. The higher the dew point, the more water vapor is in the air, and the higher the relative humidity.

The dew point can be measured with a psychrometer, which is a device that has two thermometers, one wet and one dry. The wet thermometer is cooled by evaporation, and the difference between the two temperatures is the dew point.

Why Are Some Places More Humid Than Others?

There are a few reasons why different places have different levels of humidity. One reason is that warm air can hold more water vapor than cold air. So, places that are warm year-round, like the tropics, tend to have higher humidity than places that are cold year-round, like the Arctic. And in fact, arctic places like Antartica are as dry as can be with a relative humidity as low as 0.03%! (won't have to worry about the humidity while running there…)

Another reason has to do with how air moves around the planet. Warm air rises, and as it rises, it cools off. This cooled air can't hold as much water vapor, so the water vapor condenses out of the air and falls back to the ground as rain or snow. This is why mountains tend to be drier than the valleys below them.

The Effects of Humidity on runners

The most obvious effect of humidity (other than making you feel wet and sticky) is that it makes you sweat more, which can lead to dehydration if you're not careful.

In addition, humidity makes it harder for your body to cool itself down. And when you are at full stride going for new personal bests, it is very important to get that body cool.

While you may see some marathoners strap themselves in ice packs on a hot day before a race, most of the rest of us simply use our own sweat. Sweat is a very important mechanism we have to cool off. When you sweat, evaporation is one of the ways your body releases heat.

In high humidity, there is more water vapor in the air, so evaporation happens more slowly. This is why your clothes get so wet with sweat running in humidity, they just can't dry out with all the water in the air.

But this is also dangerous, because your body can't cool off effectively, this can lead to heat exhaustion or even heat stroke. And those sweat soaked clothes…they will actually trap in heat and make things even worse!

Additionally, high humidity can make it difficult to breathe. When the air is full of water vapor, it can be harder for your lungs to get the oxygen they need. You may feel like you are literally sucking in water. This can lead to extra shortness of breath while running.

Tips for Running in Humidity

There's no way to completely avoid the effects of humidity, but there are some things you can do to make it easier to run in high humidity.

1. First, make sure you stay hydrated. This is important any time you run, but it's even more important in humid conditions. Drink plenty of water before, during, and after your run. Even if you don't feel thirsty! Because humidity prevents you from cooling off, you sweat more and lose more water.
2. Second, dress appropriately. Wear light, breathable fabrics that will help you stay cool and dry. Avoid cotton, which will hold onto sweat and make you feel even hotter. This is the time to go running shirtless or in a sports bra.
3. Third, run early in the morning or late at night. The temperature is usually cooler during these times. However, sometimes in the morning you may experience even more humidity before the sun burns out some of that water vapor.
4. Finally, take it easy. If you're not used to running in high humidity, don't try to push yourself too hard. Start with shorter runs, and gradually increase your distance as you get used to the conditions. You may find you are only capable of running slower, and that is perfectly OK. Just listen to your body and don't overdo it.

Summary

Humidity can make running feel a lot harder than it actually is. But with a little preparation, you can make it through your runs without too much trouble. Stay hydrated, dress appropriately, and take it easy, and you'll be fine.