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.
Signs and symptoms. Heat exhaustion or heatstroke can develop quickly over a few minutes, or gradually over several hours or days. Signs of heat exhaustion can include: tiredness and weakness. feeling faint or dizzy. a decrease in blood pressure. a headache. muscle cramps. feeling and being sick.