What physiological response usually occurs as a consequence of heat stress?

The correct answer is increased sweating. During heat stress, the body needs to regulate its temperature to prevent overheating. Sweating is a primary physiological response that helps achieve this. When sweat evaporates from the skin surface, it cools the body, effectively helping to maintain a stable internal temperature despite external heat.

The mechanisms involved in sweating are initiated when the body's core temperature rises. The hypothalamus, which acts as the body’s thermostat, triggers sweat glands to produce perspiration. Thus, increased sweating is a key strategy for thermoregulation during periods of elevated temperature or physical exertion in hot environments.

In contrast, other options do not align with typical responses to heat stress as they either suggest opposite actions or processes that are not directly related to heat regulation. For example, decreased heart rate and decreased respiratory rate would not help in cooling the body effectively; rather, the body generally responds to heat stress with increased heart rate and respiratory rate to enhance blood circulation and support the cooling process. Similarly, an increased metabolic rate is not a direct response to heat stress; rather, it may occur during physical activity, but it does not aid in responding to heat stress itself.