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 posted by Dru! on Flickr

Our news ticker has been lit up recently with the news of the recent settlement of a lawsuit where an Indiana man passed away after collapsing in the sauna of his YMCA. We feel deep sympathy for the man’s friends and relatives, as losing a loved one suddenly is always difficult, especially when you’re not dealing with individuals, but through the American legal / insurance system, as was the case for this man’s poor wife. But that’s a topic for another blog.

This brings the topic to light that heat bathing can be dangerous. According to Wikipedia, raising your core body temperature just 6°F / 2°C can be life threatening. Any additional temperature rise can begin to cause brain damage. For pregnant women, the dangers to their unborn child begin sooner, with a core temperature rise to 102.0°F /38.9°C. Normal body temperature is 98.6°F / 37.0°C.

In 1991, The American Journal of Public Health published a review of “The Health Hazards of Saunas and Spas and How to Minimize Them.” Most of this article is a review of the literature published to date, much of it in the 1998 Annals of Clinical Research special edition on saunas. (We have not been able to find this publication. If you have a copy, we would be grateful if you would share this with us.)

In the study, the author recommends:

Persons with heart disease, hypertension, seizure disorders, diabetes, or significant obesity; persons who have ingested alcohol, narcotic drugs, or medications that can result in drowsiness or interfere with the body’s temperature-regulating mechanism; or persons who are over 65 years of age must limit their stays in saunas or spas to 5 or at the most 10 minutes at a time. Similar precautions should be observed by women in the first trimester of pregnancy.

Even healthy adults would be well advised not to stay in for more than 10 to 15 minutes at a time.

Fainting is the greatest hazard for heat bathers. In a test of 60 otherwise healthy adults, 5% of them fainted after a 20-minute sauna session. The test was repeated with 61 children under 12, and 3% of them fainted after a 10-minute sauna session. The author notes that if you have heart disease, or have used alcohol or drugs your risk of fainting increases.

Falling from fainting while in or exiting the bath can cause injuries by itself, or compounded by the hot stove components. Fainting with loss of consciousness, especially in an unsupervised area,  can cause more severe problems if you are not promptly removed from the heat or water.

Heart arrhythmia can  be caused by sauna bathing. This is especially true if you have heart disease, or arteriosclerosis. What many people don’t realize is that alcohol, cocaine and other drugs that affect the heart, temperature regulating mechanisms, or cause drowsiness, can also increase your risk for cardiac arrhythmia. This carries over into the hangover phase as well.

Sweating out a hangover in a sauna is a bad idea.  Evidence presented in the paper shows that if you are hung over, you are more likely to experience cardiac arrhythmia in the sauna. Even the wild children at Partiers.com admit it is as bad as “Hair of the Dog.”

As part of this study, the author polled US medical examiners about heat bathing related deaths from 1983-1988. Of the 7 sauna-related deaths in that period, 6 were in people who had used alcohol or had heart disease. All were over 12 years old, and 5 of the 7 were over 65 years old.

In that same time period, 47 spa / hot tub deaths were reported.  45% of the fatalities had used either alchohol and/or cocaine. Another 17% of these were people with heart disease.

Other hazards found in the study were:

• Diabetics taking insulin via injection can absorb it more quickly due to dilation of the blood vessels near the body surface.
• Men whose partners are trying to conceive should avoid the sauna: A single 20-minute exposure to a sauna at 176°F / 80°C can decrease sperm count for up to 5 weeks!
• Women who are or may be pregnant should be careful around the sauna: A small temperature rise in your body can damage your unborn baby, especially in the first trimester. In the last trimester, elevated body temperatures can induce labor.

I did a quick study of sauna-related injuries from 2006 and 2007, reported by hospitals to the US Consumer Products Safety Commission. There were a total of 23 injuries in those two years. All injuries were minor enough to allow the patients to be released without admission to the hospital. Most were burns, falls or fainting episodes.  However, their data does not tell the whole story, as a family in Indiana will tell you.

Today’s New York Times reports on this study performed by a team of Austrian researchers that studied the incidence of common colds in a population of 50 people over six months. Half of the population took saunas regularly, the other half was the control, and were not permitted to use the sauna during the test period.

The study concluded that the sauna bathing population had significantly fewer cases of the common cold than the non-sauna bathing population. After three months, the sauna bathing population had half as many incidents of the cold as the control. Both groups, after they contracted a cold, had no difference in the duration and severity of the symptoms.

If I can cut my colds in half, can I deduct my sauna addiction as a qualified medical expense? The IRS says no.

[PubMed.gov] via the New York Times