If calcium levels are low and PTH levels are normal or low, then PTH is not responding properly and the person tested probably has hypoparathyroidism. Hypoparathyroidism is a failure of the parathyroid glands to produce sufficient PTH.
Heat exhaustion definition and facts. 1  Heat exhaustion is one part of the spectrum of heat-related illnesses that begin with heat cramps, progresses to heat exhaustion, and finally to heat stroke.  The body cools itself by sweating and allowing that sweat to evaporate.
The main cause of heat exhaustion is failure of the body's cooling mechanism (mainly evaporative sweating) to maintain a normal core body temperature, resulting in the body overheating. This can occur in adults, children and animals (dogs and cats, for example).