Arm Pit test With the temperature rising, cases of heat cramp, heat exhaustion and heat stroke are expected. This trend will continue in coming months with the rise in heat index, though the overall temperature of the environment may be low but the humidity will be high. It is the heat index, which decides occurrence of heat exhaustion and heat stroke. With high humidity, the heat index may be much higher in the presence of relatively low environmental temperature. One should differentiate between heat cramps, heat exhaustion and heat stroke. In heat stroke, the internal temperature may be very high and may not respond to injectable or oral paracetamol. In such cases, the temperature of the body needs to be lowered over minutes and not hours. Clinically, both heat exhaustion and heat stoke may have fever, dehydration and similar symptoms. The main difference will be abnormal “arm pit test”. Normally, axillae will always be wet even if a person has severe dehydration. If the axillae are dry and the person has high fever, this invariably means that the person has progressed from heat exhaustion to heat stroke. Such a situation should be treated as a medical emergency.