Perspiring is part of the complex thermoregulatory process of the body that increases the heart rate, cardiac output, and metabolic rate, causing the body to burn calories. That’s a fancy way of saying that sweating is actually a workout! Studies have shown that a 40-minute infrared sauna session can burn upwards of 400 calories. In just a 3-month period, regular infrared sauna sessions have been shown to reduce both weight and waist circumference.