Dry vs. humid environments

Global heat waves are approaching and exceeding the critical environmental limit.

In hot, dry environments, the critical environmental limits aren't defined by wet-bulb temperatures because almost all the sweat the body produces evaporates, which cools the body.

The cutoffs are based on keeping your body temperature from rising too much. Even lower temperatures and humidity can stress the heart and other body systems, and prolonged exposure may become extreme for the elderly and those with chronic diseases.