Heat exhaustion is volume depletion, which may lead to shock. The person loses salt and water in various combinations without adequate replacement. It occurs in a hot environment over a longer period of time than heatstroke, in the unacclimatized individual engaged in strenuous physical activity, and in the elderly. The temperature is normal or slightly elevated. In contrast to heat stroke, sweating is present, and the person is often cool and clammy. Neurological symptoms are absent. It may progress to heat stroke.
4 liters of IV normal saline or Ringers lactate administered over 3 hours.
Heat cramps are caused by salt depletion from sweating. It is seen after strenuous physical exercise and involves painful spasms of leg muscles from hyponatremia which interferes with calcium-dependent muscle relaxation. The temperature is normal.
2 liter bolus of IV normal saline.