Bamboo briefs and what makes them comfortable in heat

Short answer: In the heat, it is moisture between skin and fabric that causes discomfort. Bamboo viscose moves moisture on into the air, and a cut that does not chafe removes most of the rest of the problem on warm days.

Moving moisture rather than soaking it up

Cotton soaks up moisture and holds on to it, so the fabric turns heavy and clammy against the skin. Bamboo viscose moves the moisture on and releases it into the air. You notice it most when it is warm, because you sweat more and the fabric has to work all day. See bamboo briefs.

Why evaporation feels cool

When moisture evaporates from the skin, it carries heat away. That is how the body cools itself. A fabric that holds moisture slows the process, while a fabric that lets it escape helps. So comfort in the heat depends less on the temperature of the fabric and more on where the moisture goes.

Chafing between the thighs

In the heat, skin swells slightly, and thighs that touch rub against each other all day. It can turn sore and red. A cut with a little leg solves it, because fabric on fabric glides where skin on skin grips. Many wear short shorts under dresses and skirts. See bamboo under shorts.

Loose or close fitting

A cut that sits close without squeezing is often better in the heat than one that is too loose. Loose fabric bunches into folds, and folds rub. Tight fabric presses and traps warmth. Choose the size that lies smooth against the body, and avoid elastic that leaves deep marks.

Change more often

In the heat, change your underwear daily, and more often if you have sweated through. It feels better and gives the skin a break from moisture. With a long day ahead, a spare pair in your bag is a good idea. Then there is less reason to walk around in something clammy. See bamboo underwear for women.

The clothes on top matter too

Even the best underwear struggles under dense synthetic trousers. Airy materials on top let moisture escape, so the underwear does not become saturated. On the hottest days, choose a loose dress, a skirt or trousers in a breathable fabric. The layers then work together rather than against each other.

Wash without fabric softener

Fabric softener leaves a thin film on the fibres, and that film blocks the very moisture transport that makes the difference in the heat. It is the one laundry mistake that costs most in summer. Wash at 40 degrees and leave the softener out. Read more under washing and care.

Dry fully before wearing

Underwear that goes into the drawer slightly damp never feels quite fresh, and in the heat you notice fast. Let it dry completely, ideally in the shade or on low heat so the elastic is not harmed. Bamboo viscose dries fairly quickly on a line, especially on warm days with dry air.

In short

Comfort in the heat comes down to moisture and chafing. Choose a fabric that moves moisture on, a cut that lies smooth, and under shorts if your thighs rub. Change often, wash without softener and let your underwear dry fully. The warm days then become easier to get through.

Frequently asked questions

Is bamboo cooler than cotton?

It moves moisture away from the skin faster, and evaporation is what cools. The fabric itself is not cold, but it does not hold on to sweat the way cotton does.

How do I avoid chafing in the heat?

Choose a cut with a little leg or wear under shorts beneath your dress. Fabric on fabric glides where skin on skin grips and turns sore after a long day.