Thermoregulation in clothing and what fabric can do

Short answer: Fabric cannot heat or cool by itself. It can move moisture and trap air, and those two things decide how you experience temperature.

What actually happens

The body regulates its temperature by sweating and by changing blood flow. Clothing's role is to help or to hinder. A fabric that moves sweat away helps the body cool. A fabric that traps air helps it stay warm.

Why bamboo viscose feels cooling

The fibre absorbs moisture quickly and releases it to the air. When sweat evaporates from the fabric rather than sitting on the skin, it feels cooler. That is a real effect, but it is not cooling in itself. See bamboo underwear for women.

What is not true

A fabric cannot measure your body temperature and respond to it. Claims that a material warms in winter and cools in summer are about moisture and air, not intelligence in the fibre. See bamboo nightwear for women and bamboo clothing for women.

Frequently asked questions

Can one bamboo layer be used in both summer and winter

Yes, as a first layer. In winter it just needs an insulating layer over it.

Is wool better at temperature regulation

Wool holds warmth better when damp. Bamboo cools better in heat.

Are there fabrics that really regulate temperature

There are materials that absorb and release heat through phase change, but the effect is small in ordinary clothing.