What is a primary indicator of heat stress?

A primary indicator of heat stress is a lack of sweat. When the body is exposed to high temperatures, it typically responds by sweating to facilitate cooling through evaporation. However, in cases of heat stress, particularly when the body becomes overheated or dehydrated, the ability to sweat diminishes. This lack of perspiration can signify that the body's cooling mechanism is failing, which is a critical sign of heat stress.

While increased heart rate, dehydration, and fatigue can also be associated with heat stress, they are not as definitive in identifying the body's inability to manage heat as the absence of sweating. A lack of sweat directly correlates with the effectiveness of thermoregulation, allowing you to recognize heat stress issues more clearly and take appropriate action to address it.