Why you sweat more in humidity

Short answer: The body sweats to cool itself through evaporation. In humid air, sweat does not evaporate, so the body produces more in an attempt to reach its goal. That explains why a humid day feels far clammier than a dry day at the same temperature.

How sweat cools you

It is not sweat itself that cools the body. It is evaporation. When water turns from liquid to vapour, it takes heat from the skin with it. In dry air this happens quickly and almost invisibly. That is why you can sweat quite a lot on a dry day without noticing, because the sweat disappears before it collects.

The body tries harder

Without evaporation, the body does not reach its target temperature and increases sweat production. It is trying to solve the problem with more of the same. The result is more sweat that does not evaporate either. A thin inner layer, such as bamboo undershirts for men, can help spread the moisture so more of it can leave.

Sweat stays on the skin

In saturated air, sweat runs off instead of evaporating. It gathers in drops, runs down your back or stays in your clothes. That is why a humid day feels clammy even when the temperature is not especially high. Sweat that runs off the skin without evaporating does almost nothing to cool you.

Clothes need to move it away

When the air cannot take the moisture, the fabric has to do the work. A material that draws moisture away from the skin and spreads it over a larger area gives it a better chance to evaporate. It does not solve the problem fully, but it helps. See the most popular styles from Copenhagen Bamboo.

Loose rather than tight

In humid weather it helps if clothes do not sit too close. A little air between skin and fabric gives moisture a chance to escape. Tight clothes keep sweat trapped against the skin. Choose a fit with some room, especially on the upper body, where most people sweat the most.

Your legs count too

It is not only the upper body that sweats in humid weather. Legs can become clammy too, especially if you sit a lot. Loose, soft trousers let more air through than tight jeans. A pair of bamboo sweatpants for men can be a calm choice for humid evenings when it cools a little.

Change when you can

When clothes are wet with sweat, they hold moisture against the skin. If you have the chance, changing your undershirt in the middle of the day can be a good idea. It feels fresher and makes the rest of the day more comfortable. Pack an extra one when travelling to humid places.

Take it easy in the heat

The simplest way to sweat less is to move a little more calmly. In humid weather every activity costs more, because the body struggles to get rid of heat. Plan demanding things for morning or evening, and look for shade and air at midday. If you have questions about your own sweating, talk to your doctor.

Frequently asked questions

Why do you sweat more in humid weather

Because the sweat does not evaporate. The body does not reach its target temperature and increases sweat production, even though the extra sweat cannot evaporate either.

What cools the body

Evaporation, not sweat itself. Sweat that runs off the skin without evaporating cools almost nothing, which is why a humid day feels so clammy.

What can clothes do

Move moisture away from the skin and spread it over a larger area, so more of it can evaporate. That makes the day more comfortable, even when the air is humid.