Which physical response is a symptom of heat exhaustion?

In the context of heat exhaustion, a rapid heartbeat is a physiological response that indicates the body is struggling to maintain an adequate temperature and proper blood flow during excessive heat exposure. When the body overheats, it attempts to cool down through mechanisms such as sweating and increased heart rate. The rapid heartbeat reflects the increased demand for blood circulation to help cool down the body, as well as to support bodily functions under stress.

The other options, while they can represent discomfort or issues related to different medical conditions, are not characteristic symptoms of heat exhaustion. Severe headaches can occur due to dehydration or prolonged exposure to heat, but they are not a direct symptom of heat exhaustion alone. Uncontrollable shivering typically suggests the body is experiencing hypothermia, a condition opposite to heat exhaustion. A persistent dry cough may indicate respiratory issues or infections, which are unrelated to the body’s thermoregulation in hot environments.