Which of the following statements regarding heat stress is true?

Heat stress occurs when the body's natural cooling mechanisms are overwhelmed by environmental conditions, leading to a rise in body temperature. The correct statement highlights that high temperatures, humidity, and direct sunlight substantially contribute to heat stress. When the temperature rises, the body struggles to dissipate heat effectively, particularly when humidity is high, as moisture in the air limits sweat evaporation. Additionally, exposure to sunlight can add to the heat load on the body, further exacerbating the risk of heat-related illnesses. Understanding these interactions is crucial for preventing heat stress, especially in outdoor or physically demanding work environments where proper hydration and cooling strategies should be emphasized.

The other statements do not accurately address the nature of heat stress. Personal protective equipment can indeed affect heat stress levels, as certain types of PPE can trap heat. Heat stress is distinct from pesticide poisoning, which has its own symptoms and causes; they are not synonymous. Lastly, physical exertion generates internal heat in the body, so hard work definitely contributes to the body's heat production, which in combination with external factors can intensify the effects of heat stress.