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Find here the ten important questions about Radon

EURADON - European Association radon spas eV has published a booklet with 10 questions on Radon therapy. 


What is radon?

Radon, more exactly radon-222, is a natural radioactive gas, that is colourless and tasteless. The source of this gas is the radium contained everywhere in the earth's crust, a metal which in turn is produced by the decomposition of uranium. 

The physical half-life of radon is 3.8 days, whereas the biological half-life is only 20 - 30 minutes. Thus, half of the radon intake has left the body within this time. Only few hours later no radon can be verified in the body anymore.  

The discussion about radon-risk does not concern radon itself, but mostly its degradation products, especially polonium, bismuth and lead. 

Some of them can stay in the body while radon, as a noble gas, does not enter into any chemical compounds in the organism. However, only one to two percent of the radon decays in the body, so that the proportion of secondary products is very small. The special biological effect of radon is due to the extraordinary high-energy alpha rays that form when decaying. Therefore, very low doses are enough to achieve an effect. 

Where does radon occur?

Radon is found everywhere in the earth crust, in water and in the air. Radon levels vary greatly according to the region. Radon is especially high in places where a great deal of rock containing uranium occurs and where the ground is very gas-permeable. It occurs for example in the German mountains of: Erzgebige, Fichtelgebirge, Frankenwald, Oberpfalz, Bavarian Forest, Hunsrueck, the Austrian mountains of “Hohen Tauern and Waldviertel. 

If spring water is surrounded by a great amount of radon gas in the ground, the springs may also contain radon.  

Radon also occurs in houses and apartments, depending on how impermeable the subsoil beneath the building is. 

Every person absorbs natural radioactive substances via breathing and food. In average a person in Germany is exposed to natural radioactivity amounting to 2.4 mSv (milli-Sieverts) every year. Radon makes up more than half of it with about 1.4 mSv of natural radiation.  

The Sievert (Sv) unit of dosage expresses the biological effect of radiation on the human body, which depends on the type of radiation and its susceptibility on parts of the body affected. 

Further to natural radiation, is also radiation triggered by civilisation sources, which result in an average value of 1.6 mSv. This level of contamination is mainly due to the medical sector, primarily x-rays. 

Which biological effects of radioactivity are known?

In the case of ionizing radioactivity, energy is transmitted, which triggers changes within the cells in the human body. Radiation experts have agreed that exposure to large doses of radioactivity can cause cancer or harm to unborn children in their mother's womb.  

However, experts do not confirm the risk to health posed by very low doses of radioactivity.  

There is disagreement over the question: what is the health risk for very low-dose radiation? There is verified evidence from animal experiments and population studies that low doses of radioactivity may even be beneficial to health up to a threshold level. The Balneologists assume that low doses radiation in the form of a radon application in the organism stimulates cells and organs.

This positive effect of small doses, as opposed to the damaging effect of large doses, is called hormesis (hormao = Greek "to stimulate, excite"). This hormesis theory contrasts with the theory of a linear dose-effect relationship without any threshold value. Purely for precautionary reasons, the German office for Radiation Protection maintains the view that radiation even in very small doses might still be dangerous. However, this is a purely theoretical assumption, as it is only based on calculations. Up to now no evidence has been provided suggesting that any danger to people's health is posed by radioactivity in small doses.  

Can radon trigger beneficial reactions in the human body? 

Balneologists noticed long lasting anti-inflammatory and pain-relieving effects. Meanwhile there is a great deal of evidence to explain this effect by scientific basic research work:

The ability of cells to repair themselves with regard to defects in a person's genetic inheritance is improved by alpha radiation. Each cell naturally has the capability to recognise and eliminate disfunction. 

If cells are initially exposed to low doses of radiation and afterwards to larger doses, the normal damage triggered by larger doses of radiation is avoided. 

Radon or its decay products are accumulated in fatty tissue and in the central nervous system during radon treatment.  This could lead to an increased hormone production level.

The pain-relieving effects of radon treatment are also partly due to the release of endorphins (the body's own pain-relieving substances).  

The body's own mechanism of so-called apoptosis (= cell infiltration) is activated by alpha radiation. Cells that go into apoptosis and their neighbouring cells emit anti-inflammatory substances. Immunocompetent cells that take up the apoptotic cells also produce certain healing-promoting messengers, especially the cytokine TGF-beta. (TGF-Beta is the body's antagonist of the "inflammation driver" TNF-Alpha.) This activates the self-healing powers of the body, slows down chronic inflammation from the inside and stabilizes the immune system.
 The production of radical scavengers is increased. They make free radicals harmless - destructive metabolites that for example play an essential role in rheumatic processes

How is radon therapy carried out?  

Bathing, drinking, inhaling - these are the three different types of radon therapy practised at spa centres nowadays during three to four-week spa treatments with 8 to 12 applications. 

1. Taking baths in radon-containing water; the noble gas passes through the skin into the body, at the same time the radon gas can be inhaled through the steam produced by the bath.
 2. During a treatment in a mining gallery, the patients breathe in the radon-containing air. If the patients are not clothed, radon is also
  absorbed through the skin at the same time.
 In seaside resorts with radon sources, the rising gases can also be trapped and fed to the patients via domes, so that they can inhale the mix, or you can breathe the gas in a cubicle for steam baths.
 3. When drinking water which contains radon, the bloodstream takes up radon via the gastrointestinal tract.

Is there any risk of radioactive contamination during radon therapy?

The known "Schneeberg disease" hit the headlines a century ago. Miners in the “Erzgebirge”, who were exposed to high concentrations of radon and dust for a period over many years, died from lung cancer at an early age. Studies have now established a clear link between high doses of radon and lung cancer. On this basis of these data the possible link to get a tumour during radon therapy is discussed using purely mathematical models. Experts exclude the possibility of people getting other types of cancer in connection with radon. 

We must mention that radon therapy carried out in a mining gallery involves a far lower amount of radon than was present in working mines. By way of comparison, miners were exposed to doses amounting to several Sieverts (Sv, see question 2) for a period of many years. 

Experts calculated that people receive no more than only 1,8 mSv (MilliSieverts) during a three-week course of treatment in a mining gallery. This roughly corresponds with the amount transmitted when a person's stomach is x-rayed. During bath therapy, the amount is just 1 mSv at maximum.  

Experts therefore say that balneological radon treatment represents a level of  exposure that is encountered in normal circumstances. 

Therefore, the data obtained from mining workers cannot be transferred to radon spa treatments, because the air in active mines, as opposed to a treatment in a mining gallery, is contaminated with other harmful substances that cause lung cancer, e.g. arsenic or diesel exhaust fumes and moreover fine dust.

In addition, the proportion of smokers - about every 10th smoking miner gets lung cancer - among the miners were above average. Taking these factors into account, even with the pessimistic assumption of a linear dose-response relationship without threshold value (see question 3), as represented by radiation protection on a purely precautionary basis, the lung cancer risk of radon therapy is negligibly small. Also, the data of the continuous load in living rooms with increased radon concentration cannot be transferred to the short-term radon application as part of a healing process. Radon therapy is the same as for any medical application of ionizing radiation, e.g. X-rays or Nuclear Medicine Procedures for Pain and Inflammation Mitigation: The physician must compare and weigh the benefits and risks to the patient.  

For which diseases is radon therapy advisable?

In the course of experiences with radon therapy, which has been documented for almost one hundred years, some types of diseases have been evaluated where radon treatment has been specifically effective.  

These are: 

Diseases of the rheumatic type, above all Bechterew`sche-illness (Morbus Bechterew), but also chronic rheumatoid arthritis, osteoarthritis and certain forms of soft tissue rheumatism;
Respiratory diseases, such as bronchial asthma or chronic bronchitis;
Skin diseases, such as psoriasis and scleroderma.

Radon cannot cure any of these chronic illnesses, but it can also help relieve the symptoms. In order to permanently improve the quality of life of the patients, a repetition of the treatment may be repeated every three years 

Who should not undergo a radon therapy? 

People with hyperfunction of the thyroid and pregnant women are advised against a radon therapy. Even patients with acute illness should not undergo radon therapy. Successfully treated cancer patients need an individual medical decision. In mining galleries one must not suffer from claustrophobia. In children and adolescents, the attending physician must decide on a possible use of Radon.

Are the results of radon therapy scientifically proven? 

Some hot springs have enjoyed the reputation of having particular healing power for centuries, e.g. on the island of Ischia or in Bad Gastein.  

If the healing power was once attributed to a "spring spirit", scientists discovered in 1904 that radon was the effective element in the spring water.  

Radon therapy has now been subjected to clinical studies on patients -- with positive results. All studies show that the therapeutic effect of radon carries on for several months. In carefully monitored double blind trials, where neither patients nor doctors knew which patient received radon and which didn’t, its therapeutic effect was confirmed. 

Here are some examples: 

While treating 60 patients with chronic polyarthritis, who underwent a four-week rehabilitation course at a medical centre, involving medical baths, gymnastics and other treatments, it was possible to show that carbon dioxide baths, containing radon, were more effective than those which did not contain any radon  Those patients, who were being treated with radon (15 full baths), had significantly less pain and were able to move better than the comparison group, who also had 15 baths. While the improvement achieved by the treatment in the monitored group rapidly wore off, the positive effect in the radon group could still be felt six months after the treatment. 

262 patients with ankylosing spondylitis received treatment at a medical centre for four weeks, involving rehabilitation measures including gymnastics and sport; one group of them also inhaled radon in a treatment mining gallery. They also had significantly less pain nine months later than the comparison group that had not inhaled radon. The savings in medicines is also particularly interesting in this case - especially if not 

only the expenditure is taken into account, but also the side-effects, some of which are enormous: While the monitored group only reduced its initial dose of painkillers by 1/6, and only for a period of six months, the radon group required 1/3 less painkillers a whole year after the treatment.  

In a further study with 100 patients with Bechterew's disease, who repeatedly performed rehabilitation measures within 12 years, it was shown that the consumption of analgesics remained significantly lower when the rehabilitation measures were coupled with a radon mining gallery therapy.

Russia, with more than 30 radon spa centres, has had especially good opportunities to test the effects of radon going back a long way. Radon preparations are also made up artificially there. This enabled scientists to prove that the positive effect of radon can be reproduced and is doses related as a proof of the therapeutic effect of a medical substance for pharmacologists. In addition, the radium laboratories were able to prove that the success of radon is not attributable to the general influences of the spa treatment, but actually to radon itself.  

Where is radon therapy available? 

Germany: Bad Brambach, Bad Kreuznach, Bad Münster am Stein-Ebernburg, Bad Schlema, Bad Schmiedeberg, Bad Steben, St. Blasien/ Menzenschwand, Sibyllenbad 

Austria: Bad Gastein, Bad Hofgastein, Bad Zell

Czech Republic: Jachymov (St. Jochimsthal)

Other radon health resorts are in Russia (more than 30 beach resorts), Bulgaria, Italy, Japan and Poland.
We would be pleased to send you the brochure "10 questions on radon therapy" of the EURADON consortium - Association of European Radon Spas. This contains additional information about further literature. 


Contact: Tourist Information Bad Steben, Tel. 09288 960-0 or E-Mail to