# Balneotherapy with the Use of Radon-Sulphide Water: The Mechanisms of Therapeutic Effect
## 2 The Mechanism of the Therapeutic Effect of Radon-Sulphide Water  
The mechanism of action of therapeutic waters has not been fully explored; however, their effectiveness in therapy is confirmed by many authors. It is believed that it is the result of combined action of many factors, the most important of which are thermal, mechanical, and chemical. Mechanical effects of therapeutic baths include reduction of muscle tension, improvement of joint mobility, and pain relief. Joint oedema is also reduced by increasing sodium excretion and stimulating diuresis. Such changes were observed, among others, in patients with rheumatoid arthritis [5]. The thermal effect of therapeutic baths is characterised by an increase in the secretion of hormones and various types of active proteins. Thermotherapy reduces pain by increasing the serum concentration of endorphins and activates the secretion of cortisol and ACTH (adrenoocortic hormone). Moreover, a decrease in the level of immunoglobulin in the plasma, a rheumatoid factor, an increase in erythropoietin activity, and iron activity were also observed [6, 7]. Heat increases the elasticity of tissues, i.e., tendons, ligaments, and joint capsules, thus increasing the range of motion in the affected joints and spine. The chemical effect depends on the chemical composition of the therapeutic water. The sulphur ions and radon activity of the water play a key role in the therapeutic effect of radon-sulphide water. Sulphur is an electronegative acid-forming element that occurs in many forms and in various concentrations. In the presence of oxygen, it shows a high reducing power, which leads to the formation of its various products. This is also the reason why water containing sulphur compounds is highly unstable, especially when mixed with air. Waters containing sulphur, which have been recognised as therapeutic, must contain at least 1.0 mg/dm\({}^{3}\) of iodometrically determined sulphur. Therapeutic waters predominantly contain sulphides, i.e., compounds of sulphur with metals. In the process of slow oxidation, these compounds pass through sulphur to the sulphate form. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{3}{*}{**No.**} & \multirow{3}{*}{\begin{tabular}{c} **Sample** \\ **Location** \\ \end{tabular} } & \multirow{3}{*}{\
\begin{tabular}{c} **Water** \\ **Temp.** \\ **in \({}^{\circ}\)C** \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} **pH** \\ **in \({}^{\circ}\)C** \\ \end{tabular} } & \multicolumn{3}{c}{**The Content of the Ingredient in 1 dm\({}^{3}\) of Water**} \\ \cline{4-9}  & & & & **H\({}_{2}\)S** & **HCO\({}_{3}\)** & **Rn** & **Rn** \\ \cline{1-1} \cline{4-9}  & & & & **mg** & **mg** & **nCi** & **Bq** \\ \hline
1. & Well no. II & 12.0 & 7.62 & 1.96 & 263.2 & 2.21 & 81.8 \\
2. & Well no. IX & 12.0 & 7.72 & 1.70 & 289.6 & 1.71 & 63.3 \\
3. & MSP tub & 16.0 & 7.65 & 1.87 & 277.9 & 2.20 & 81.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Results of physicochemical tests performed on 24 April 2008 at the therapeutic water springs and in mineral spring spa (MSP) (own material). Sulphide waters contain much less total sulphur compared to sulphate waters, but they contain sulphur at lower levels of oxidation, especially divalent sulphur, which is the most biologically active [8]. During a bath with sulphur content, erythema appears on the submerged part of the body and lasts from a few minutes to several hours. Dilation of most capillaries under the influence of histamine-like substances released in the skin by sulphur causes the transfer of significant amounts of blood into the skin, which also reduces blood pressure in people with normal and high blood pressure. The fragility of blood vessels is also reduced. Sulphide therapeutic water containing calcium and magnesium has an antiallergic, desensitising, antifungal, and antiparasitic effect, and it enhances immunity due to the increased production of antibodies.