If had we had evolved to live in constant cold, our bodies might have grown thick hair all over, we might store more fat, and our body shape might be rounder and shorter to prevent heat loss.

They get their heat from the outside environment ... What about all the birds and mammals that are not large, such as mice and sparrows? The other factor—body shape—comes into play here. Small ...

To approximate that effect, scientists calculate “wet-bulb” temperature ... loosen or wet your clothes to reduce body heat, or take a cool bath, if possible. Seek out air-conditioned places ...