Sauna suits, which are sweat suits made from waterproof fabric, do not burn fat. As explained in Shape, wearing a sauna suit while exercising causes quick weight loss due to sweating, but the pounds return after one consumes liquids. The weight loss is temporary and can lead to dehydration.
Losing a large amount of fluid during exercise can cause muscle cramps, according to WebMD. Feeling faint is a common symptom as fluid is reabsorbed from the blood and other tissues. If there is insufficient fluid for blood to reach the organs, the body can become severely dehydrated and go into shock, a life-threatening condition that requires emergency medical attention.