Due to the deep penetration, over 1.5 inches into the skin, of the FIR (farinfrared rays) generated by a FIR sauna, there is a heating effect deep in the muscular tissues and the internal organs. The body responds to this deep-heating effect via a hypothalamic-induced increase in both heart volume and rate.
This beneficial heart stress leads to a sought-after cardiovascular training and conditioning effect. Medical research confirms that the use of a sauna provides cardiovascular conditioning as the body works to cool itself and involves substantial increases in heart rate, cardiac output and metabolic rate.
As a confirmation of the validity of this form of cardiovascular conditioning, extensive research by NASA in the early 1980s led to the conclusion that far infrared stimulation of cardiovascular function would be the ideal way to maintain cardiovascular conditioning in American astronauts during long space flights.
Blood flow during whole-body hypothermia is reported to rise from a normal 5-7 quarts per minute to as much as 13 quarts per minute.
According to the "Wellness Letter", 10/90, University of California, Berkeley, "The 1980's was the decade of high-impact aerobics classes and high-mileage training. Yet there was something elitist about the way exercise was prescribed. Only strenuous workouts would do, you had to raise your heart rate to between X and Y, and the only way to go was to go for the burn. Such strictures insured that most 'real' exercisers were relatively young and in good shape to begin with. Many Americans got caught up in the fitness boom, but probably just as many fell by the wayside. As we've reported, recent research shows that you don't have to run marathons to become fit - that burning just 1,000 calories a week is enough. Anything goes, as long as it burns these calories."
Outstanding Calorie Consumption and Weight Control
In Guyton's Textbook of Medical Physiology, we find that producing one gram of sweat requires 0.568 kcal. The Journal of American Medical Association (JAMA) states: "A moderately conditioned person can easily sweat off 500 grams in a hot-air sauna, consuming nearly 300 kcal, which is equivalent to running 2 - 3 miles. A heat-conditioned person can easily sweat off 600 - 800 kcal with no adverse effects. While the weight of the water loss can be regained by drinking water, the calories consumed will not be."
Since a FIR sauna helps generate two or three times the sweat produced in a hot-air sauna, the implications for increased caloric consumption are quite impressive.
Assuming "a sauna", as mentioned in JAMA, to last for 30 minutes, some interesting comparisons might be drawn. Two of the highest calorie-consuming forms of exercises are rowing and marathon running. Peak output on a rowing machine or during a marathon run burns about 600 calories in 30 minutes. A FIR sauna may enhance this effect from "just slightly" up to as much as 250%, by burning about 900-2,400 calories in a 30 minute session.
The FIR sauna might then simulate the consumption of energy equal to that expanded in a 6-9 mile run during only a single session. A FIR sauna can, thus, play a pivotal role in both weight control and cardiovascular conditioning. This would be very valuable for those who don't exercise and those who can't exercise yet want an effective weight control and fitness maintenance program and the benefits of a regular exercise.