Sauna and Your Health

The effects of the sauna on health are very personal. As a rule, everybody can safely enjoy the sauna if they feel ok about it. Some additional care should be taken if the bather has a history of low blood pressure or is under the influence of alcohol or drugs, since these can strengthen the effects of the sauna.

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Blood Pressure and Saunas

On Wed, 2 Oct 1996, I received this letter:

I have a history of high blood pressure, and a friend told me that at her health club, the sauna carries a warning sign that those with high blood pressure or a heart condition should excercise caution. Is there some risk for me? I take medication, which keeps my pressure down.

The heat in a sauna actually causes the capillaries in the skin to dilate, which in effect lowers blood pressure. In Finland, high blood pressure is something of a national problem, and yet most enjoy saunas at least occasionally. One could argue that the two are related, but our high blood pressure is due more to excess salt and alcohol than anything else. On the other hand, if you suffer from a low blood pressure, you should start taking saunas slowly, so you can judge its effects personally.

A friend told me that her father suffered from migraine if he went to the sauna late in the evening. Apparently this was caused by a low blood pressure which was still lowered in the sauna. He discovered by accident that he can go to the sauna whenever he wants as long as he drinks a cup of coffee afterwards. Coffee raises blood pressure temporarily and in his case seems to compensate for the effects of the sauna.

I encourage you to try a sauna and make your own decision based on how it makes you feel.

Final advice: ask your physician. These things are always very personal. For a thorough report on cardiovascular effects, you could check "Arrhythmias and Other Cardiovascular Responses During Finnish Sauna and Exercise" from amazon.com.

Alcohol and Blood Pressure

Many people enjoy a beer or two during a sauna, and a healthy person may well indulge in such pleasures. Low blood pressure and excessive alcohol intake don't mix well with the sauna, however.

Roine, et al. studied the cardiovascular response to 10 minutes of sauna bathing (ambient temperatures, 80-90 C) in men who drank the equivalent of 1 litre of wine or 3.5 Iitres of beer just prior to the bathing. They compared those responses to those seen after drinking fruit juice. There were no differences in physiologic responses seen with and without alcohol except that alcohol induced a significantly greater blood pressure drop (23 mm Hg for systolic pressure) and a greater serum cortisol rise compared to fruit juice. The authors concluded that sauna bathing, even in conjunction with an episode of heavy alcohol consumption did not induce heart rhythm irregularities, but it did induce a blood pressure drop that might be injurious to older people, especially those with pre-existing heart disease.
Roine R, et al. Alcohol and sauna bathing: effects on cardiac rhythm, blood pressure, and serum electrolyte and cortisol concentrations., Journal of Internal Medicine 1992; 231(4):333-8. Original summary

With all this in mind, you should probably avoid combining a diagnosed low blood pressure with the effects of alcohol in the sauna. Stick to juice or water, however, and you should be able to enjoy the sauna just fine.

Weight loss

Short answer: Going to the sauna does not make you lose weight.

Longer answer: yes, you can burn calories in the sauna, but you will be better off taking a short healthy walk.

Most of any perceived weight loss in a sauna is due to sweating. The loss of bodily fluids will make you lighter for a few hours, but you will get the kilos (pounds) back very soon. You will remain thirsty and when you next drink, the fluids will be restored to your body.

Meanwhile, increased cardiac output and the cooling process make the body use its energy resources. Estimates range from 300 or even 500 calories per sauna session (30 minutes), making it comparable to walking or jogging. In the sauna the only muscles working are those of your heart. While the heart is an important muscle, you would gain more from any physical activity, be it walking or swimming. These make your muscles grow and muscle tissue burns energy even while you rest. Not only will you feel better after a workout, you will be burning fat 24 hours a day.

You will sometimes hear of boxers or wrestlers going to the sauna to lose weight. High end athletes can do this for two reasons. First, they only need to lose weight for a few hours, when they are officially weighed. They will drink a considerable amount of power drinks before entering the rink to get their energy back. Second, they are constantly monitored by their physician who supposedly knows when to stop.

I have been asked whether it makes sense to use rubber suits that promote sweating in the sauna. Not only do I consider it unnecessary, such suits could actually be dangerous since they work by blocking the most important method your body has to adjust its temperature.

Cleansing the body from toxins

Sweat baths remove toxins from your body, they say. There are some projects using saunas for drug detoxifications, others believe sweating helps in getting heavy metals out of the body. Admittedly sweating does remove impurities from the skin's pores. But does it remove toxins that are probably all around your body? I have trouble believing it.

Cholesterol

Some sauna equipment manufacturers claim that sauna or steam baths can help lower body cholesterol. I have not come across scientific evidence and remain sceptic. On the other hand, one reader wrote that taking a sauna every two days has helped him lower his cholesterol even though he did not change his eating or exercising habits. Maybe there is something.

Sweating and fluid balance

Since bathing in a sauna is supposed to make one sweat, some people have been asking about the loss of fluids and its effects on the body.

One usually goes to the heat only for periods of five to ten minutes at a time, maybe four times altogether. The amount of fluids lost during this time is easily recovererd by drinking a couple of glasses of juice for example. In Finland, many take a bottle of beer or two after a sauna. I have never heard of anybody feeling uncomfortable because of dehydration in a sauna. The most common reason for discomfort would probably be the unfamiliarity with the heat, and possibly the blood pressure drop.

More on sweating in saunas and baths.

Humidity

As a sauna is not as steamy as a Turkish bath, one sometimes hears the term "dry sauna." This does not mean the air in the sauna should be dry. Entirely dry, hot air is potentially damaging to one's respiratory system. The true Finnish sauna always includes löyly. Although splashing water on the rocks first causes a surge of hot steam from the heater, it eventually cools down the sauna. Also, a more humid sauna will induce more sweating.

All sauna heaters should be built in a way to allow water to be thrown on them. With an electric heater the steam is not always pleasant if the water is only thrown onto the rocks. Try splashing some water on the walls of the sauna before bathing, it makes the atmosphere more pleasant.

Fertility

The Finnish population has survived so far, so I'm guessing the sauna can't be all that bad. Still, some studies suggest the extreme heat has some consequences.

The human body has an amazing temperature control system, allowing it to maintain the body temperature constant even in external temperature extremes. Body temperature might only change a fraction of a degree during all of a sauna bath. Normal testicular funtion needs a lower temperature than the rest of the body, however, and extreme heat may have some effect. But don't take my word, here are a study and a parenting site reporting heat has an influence on male fertility and a sauna manufacturer's site citing studies saying it doesn't.

If you enjoy the sauna, and feel relaxed and fresh after one, I believe it more than balances for any negative effects the heat might have. Having a child is so much more than just chemistry - as any couple trying to conceive probably knows better than I do.

Pregnancy and children

Pregnant mothers should probably not start taking saunas. If you are familiar with saunas, however, there is little reason to stop just because of the pregnancy. Although high temperatures have been linked to birth malformations in some rare cases, most Finnish mothers go to the sauna during their pregnancy and have a very low occurrence of these malformations compared to other similar countries.

We are not born with a fully functional temperature control system and you should not take your child into the sauna without some precautions. Once the child has some control of her body and can make her discomfort understood, you can try a sauna with her. Take it slowly and make sure the child can leave as soon as she wants. Do not start with a hot sauna, and allow the child to stay on the lower benches, where it is relatively cooler.

I Finland more than half the children experience their first sauna during their first year and most do so before their second anniversary. More.

Sports

You can safely follow physical activity with a relaxing sauna. If you work out hard, you should have a drink before the sauna, since you will already have lost fluids from sweating. Take a shower before entering the sauna, as well. This will help keep the sauna clean.

One no-no is treating injuries in the sauna. Muscle and tissue injuries should be treated with cold, compression and elevation first. Heat therapy can be applied after two days' healing.

Craig Horswill, Ph.D., at Gatorade Exercise Physiology Laboratory speaks on the combined effects of sauna and physical activity.

Other health issues

Does sauna cause hair loss? I am not aware of any study linking saunas or steam baths to hair loss. It is possible that there is a connection but I have never heard of such suspicions. I would actually suspect the opposite, since sauna can help blood circulation in the epiderm (skin). This should rather make the hair stronger than weaker.

Diabetes? Again, I am not aware of sauna being harmful for diabetics, but have no medical data to back this up. Please talk to your physician.

Please write to me if you have personal experiences that would be of interest to other sauna enthousiasts.

More on health issues

Disclaimer

Check with your physician. If you do not feel comfortable in a sauna, maybe you should do without it. This information is provided for educational purposes only. Consult your own physician regarding the applicability of any opinions or recommendations with respect to your symptoms or medical condition.