Which statement about heat stress is true?

Lack of sweat is indeed a significant symptom of heatstroke. In heatstroke, the body's thermoregulatory system fails, leading to an inability to sweat despite high internal temperatures. This is a critical distinction because sweating is the primary method by which the body cools itself. When someone is in a state of heatstroke, their core body temperature can rise dangerously high, and their body can no longer produce sweat to dissipate heat. This absence of sweat, along with other severe symptoms like confusion or unconsciousness, underscores the seriousness of heatstroke and the need for immediate medical attention.

Other options reflect either misunderstandings about the physiological processes associated with heatstroke or misinterpretations of symptoms. It's important to be cautious when engaging in activities that expose individuals to high temperatures, ensuring that they remain hydrated and monitored for signs of heat-related illnesses.