Heat exhaustion is most likely to occur in which condition?

Heat exhaustion is a condition that arises when the body becomes overheated, typically as a result of intense physical activity in high temperatures and humidity. When the environment is characterized by high temperatures combined with high humidity, the body's ability to cool itself through sweating is significantly impaired. This decreased efficacy in cooling can lead to an increase in body temperature, elevating the risk of heat-related illnesses, including heat exhaustion.

In humid conditions, sweat does not evaporate effectively, reducing the cooling effect that sweating provides and making it more difficult for the body to maintain a normal temperature. This is why individuals engaged in physical activities during such conditions are at a heightened risk for experiencing symptoms of heat exhaustion, which can include heavy sweating, weakness, nausea, and dizziness.

Conversely, the other options describe scenarios that are less conducive to the onset of heat exhaustion, such as cool weather, snowy conditions, or even indoor exercise, where temperature and humidity can often be controlled or are not at extreme levels that would lead to overheating.