What is a common symptom of heat cramps?

Muscle spasms are indeed a common symptom of heat cramps. These cramps typically occur during or after vigorous exercise in a hot environment, primarily affecting the muscles that are actively involved in the activity, such as the legs. The spasms are involuntary contractions that can cause considerable discomfort and hinder performance.

While nausea, confusion, and excessive sweating can be associated with heat stress or heat-related illnesses, they are not the hallmark symptom of heat cramps specifically. Nausea might indicate heat exhaustion, confusion could be a sign of more severe heat-related illnesses such as heat stroke, and excessive sweating is a general response to elevated temperatures but does not specifically identify heat cramps as directly as muscle spasms do. Therefore, muscle spasms are the primary and defining symptom that characterizes heat cramps.