SaunaScape

photo by whoaitsaimz on Flickr

You can’t explore “sauna” on the internet very long without coming across infomercial style weight loss claims: “Lose weight fast! With our new Super Sauna, you’ll be burning up to 600 calories every half hour, all without moving a muscle! Act now! Operators are standing by!”

Meanwhile, the fitness gurus, like Chris Klebba all say “the effects of saunas on weight loss are due to a loss of water from sweating, not actual fat loss. Bottom line, forget it for fat loss.”

So who’s right? Well in a strange twist of science, both of them are wrong! Saunas do help with weight loss by helping the body to equalize the hormones that control our desire to overeat. Interestingly, they also help those who don’t eat enough to eat more. Better still, regular sauna users have better circulation, which can help prevent  atherosclerosis, and reverse the effects of coronary heart disease.

These are conclusions from a 2003 study that was conducted at Kagoshima University in Japan, where a team of researchers studied the effects of thermal therapy on lifestyle diseases. The study began as a test to see if heat bathing could be used as a way to improve the health of patients with congestive heart failure. The team noted improvement in both the symptoms and cardiac function of their subjects after a single session, and continued improvement with additional, regular sessions.

When they examined the underlying mechanism of these improvements, they hypothesized that a similar improvement in the health of paitents with lifestyle-related diseases such as hypertension, diabetes, high cholesterol, smoking and obesity could also be improved with sauna therapy.

They tested a group of “at risk” people, who each had one or more of these conditions, and were not receiving treatment for any of these. What they found surprised them. After 2 weeks of daily sauna therapy at 140°F / 60°C, where their body temperature was elevated by 2°F / 1°C for 30 minutes, they found that blood pressure was significantly lowered.

Surprisingly, fasting plasma glucose, and body weight also went down for the group.

To study this further, they repeated the study with a group of 5 men and 5 women. For 2 weeks, they all ate a controlled diet of 1800 calories / day, and each took a single sauna session each day. At the end of the period, all 10 had lost weight, with their collective body fat falling from an average of 42% to 37%.

They did not attribute these results to calorie burn in the sauna, but instead to a better regulation of the body’s hormones that control appetite. They found that during the period, none of the subjects were not hungry as quickly, and did not tend to overeat or snack between meals.

The opposite effect was seen in coronary heart disease patients who were under eating as a result of their disease. Regular sauna sessions improved their appetite, and increased the quantity of food they consumed.

For the infrared marketers out there: Yes, this study was done in an infrared sauna, but they cited other similar research that was done using a hot bath. So these effects are not just for IR Sauna users.

[Clinical Implications of Thermal Therapy in Lifestyle-Related Diseases] via Stephen Colmant

Photo by Tsja! on Flickr

Tim Ferriss, author of the highly recommended “The 4-Hour Workweek“, added a thought-provoking post to his blog today: “How to lose 30 pounds in 24 hours.” It describes his techniques for dropping weight in advance of the weigh-in for competitive sports.

Now, most times, sauna is not a competitive sport, and even when it is, it’s not divided into weight-based classes. So what is interesting to the average sauna-goer? Water, and how your body deals with it. Some of his interesting points follow:

If you weigh 200 lbs., 120 of those pounds are water, which is distributed between three systems: blood, cell interiors (as pertaining to powerlifting, muscle fibers), and the spaces between the blood vessels and the cells dependent on them. Approximately 8% of your total water volume is contained in blood plasma, 67% is contained in the cells themselves, and 25% is found in the spaces between the two, which includes subcutaneous water.

His point being that you can “safely” lose 25% of your body weight in water. Though this is not recommended long-term:

Ball State University research has demonstrated a 7% decrease in speed over 10 kilometers by runners dehydrated by just 2%-3% of total body mass. For a 150 lb. (68 kg) strength athlete, this represents a very meager 3-4.5 lbs. (1.4-2 kg) of water loss.

Of course, the most interesting revelation for me was not about the fluids you drink, but the fluids you absorb through your skin:

The author has seen elite wrestlers make the mistake of taking a shower the morning of weigh-ins, only to find they have gained 2-3 lbs. (1-1.4 kg)!

So that shower you take before and after your sauna isn’t just cooling you down. It’s actually rehydrating you.