Infrared Radiant Heat (IRRH) is a form of radiation that penetrates the outer surface of objects, including human skin. Heat is generated as the infrared energy interacts with and penetrates the skin surface.
The depth of penetration is estimated to be 2-3 inches. The IRRH reaction is exothermic. The release of heat, if localized, is believed to be therapeutic by some health experts.
Today, a number of businesses sell saunas equipped with infrared radiant heat (IR Saunas). They claim that at 2-3 inches deep, the release of heat is beneficial in many ways. For instance, chronic wounds tend to heal.
How? No one knows for sure, but most likely it's related to improved blood flow and oxygenation of the wound. I have no problem with the theory behind IRRH and the healing of chronic wounds.
But what about weight loss? Can infrared heat cause significant weight loss? More importantly, can it lead to Healthy Weight Loss? The business owners selling IR Saunas seem to think so.
So the question is, can IR Saunas lead to Healthy Weight Loss?
Infrared Radiant Heat Saunas (IR Saunas)
Unlike older steel counterparts, IR Saunas are ceramic-coated and tend to be more efficient, producing the same amount of heat in a shorter time period when compared to the steel based saunas.
According to supporters of IR Saunas, this efficiency translates into longer exposure times, up-regulation of your body's thermoregulatory system, and weight loss.
A local Dallas newspaper printed an ad for an infrared sauna that stated , "Perspiring is part of the complex thermoregulatory process of the body that increases the heart rate, cardiac output, and metabolic rate. The process requires a large amount of energy and reduces excess moisture, salt and subcutaneous fat. Fat becomes water soluble at 110 degrees (F) leading to fat loss." -- Dallas Voice, February 12th, 2005
There is no doubt that we could pick apart the ad and question it's validity. But, I decided to keep things simple and focus on one aspect of infrared weight loss...the thermoregulatory process.
According to the advertisement, infrared heat penetrates deeply into tissue and up-regulates the thermoregulatory process. Is this up-regulation enough to cause significant healthy weight loss?
For our purposes, healthy weight loss is defined as fat loss. Remember, a healthy diet program promotes weight loss in short increments, never losing more than 2 pounds per week. The drop in weight is from a loss of fat and nothing else. Weight loss by any other means isn't healthy and should not be considered as an option for losing weight.
The Thermoregulatory Process
This is a very complex topic. Many factors are involved in keeping your body temperature constant. In the human brain, the hypothalamus regulates the entire thermoregulatory process with the exception of early responses to high temperature. Things like sweating, rapid breathing, and increased blood flow to the arms and legs are examples of the early responses not regulated by the central nervous system.
The question is can these mechanisms cause weight loss by "burning" fat. Cedric Bryant, chief exercise physiologist for the American Council on Exercise, says no.
"The amount you sweat is indicative of your body's ability to maintain its normal body temperature. You sweat when your body starts to store heat so you can experience cooling via evaporation of that sweat. So it doesn't correlate to how much energy, or calories, is being expended. You are not going to utilize stored fat simply by raising body temperature...it's not going to happen."
It makes sense too. Your body loves to store fat for future emergencies and it won't give up the fat very easily. You are well protected from starvation.
Joe King, editor for the Journal of Hyperplasia Research said, "Evaporation accounts for increases in total oxygen uptake, which causes the working muscles to utilize more glycogen." Glycogen is the stored form of glucose, the main energy source for your body.
In short, IR Saunas do not cause weight loss through utilization of fat. Instead, the high temperatures result in glycolysis (using sugars for immediate energy needs) and the water loss accounts for the drop in weight. What does this all mean? Infrared Saunas promote unhealthy weight loss.
This reminds me of what a sales representative told me a month or so ago about IR Saunas. He said, "The heart receives a workout similar to a 6-mile run in an IR Sauna." He may be right, but it's not fat that you're losing.
Conclusion
An infrared sauna is not a good option for losing weight.
Healthy Living!

Michael A. Smith, MD

The Weight Loss Professional
Additional information on can be found at The Weight Loss Professional Website.