A large number of patients are treated in various countries with the traditional radon spa therapy. Adequate oxygen stress induced by radon inhalation activates chemical biological protective functions, such as induction of the synthesis of superoxide dismutase (SOD) and glutathione peroxidase. We previously reported that radon inhalation elevated antioxidant enzymes in patients with bronchial asthma and osteoarthritis 1), 2). Objectives: Although many clinical studies have been reported, the reason why radon inhalation results in positive effects is still unclear. To elucidate the probability that activation of chemical biological protective functions alleviates various oxidation injuries, we studied the mechanisms of the effects of radon using small animals. Methods: To examine whether radon inhalation activates antioxidative functions in mice, we developed a new facility for exposing small animals to radon and examined SOD activity, which is an antioxidative enzyme, in plasma, liver, pancreas, heart, thymus, kidney, brain, small intestine, lung, and stomach of mice. Mice were exposed to radon at a concentration of 250, 500, 1000, 2000, or 4000 Bq/m3 for 0.5, 1, 2, 4, or 8 days. Results: It was shown that continuous exposure to radon increases SOD activity in most organs of mouse. In addition, our data suggested some new indications for radon treatment3). Next, we assessed whether radon inhalation provided protection from carbon tetrachloride (CCl4)-induced hepatic and renal damage in mice. Results showed that radon inhalation inhibited CCl4-induced hepatic and renal damage in mice due to activation of antioxidative functions in liver and kidney4). Although hepatic and renal damage are not the main indication for radon therapy, radon inhalation mitigates liver and kidney damage due to activation of antioxidative functions in liver and kidney. This antioxidative effect against CCl4-induced hepatopathy is comparable to treatment with ascorbic acid (vitamin C) at a dose of 500 mg/kg weight or α-tocopherol (vitamin E) treatment at a dose of 300 mg/kg weight and is due to activation of antioxidative functions5). We also suggested radon inhalation inhibits streptozotocin (STZ)-induced type I diabetes in mice due to activation of antioxidative functions in pancreas. Conclusion: Thus, radon inhalation very likely activates the defense systems in the body, and therefore, contributes to preventing or reducing reactive oxygen species (ROS)-related injuries, which are thought to involve peroxidation.

Purpose: We have previously reported the physiological and biochemical effects of bath salts. In this study, we used bath additive containing artificial carbon dioxide and sodium chloride (S bath additive), and the acute effects of bathing once with S bath additive and chronic effects of daily bathing with S bath additive for 15 consecutive days were compared with the effects of bathing once in plain water. Improvement in 10 symptoms was investigated using a 5-point verbal rating scale (VRS). Methods: Nine patients aged 51-82 years (mean, 66.6 years) with cold intolerance and lower leg pain were treated with balneotherapy. Whole-body bathing at 40°C was performed for 10 min daily (day 1, bathing in plain water; days 2-16, bathing with S bath additive). On days 1, 2, and 16, changes in patient’s subjective symptoms were evaluated using a VRS ranging from -1 to +3. Results: Compared with bathing once in plain water, bathing once with S bath additive was improvement of coldness, body warmth, blood circulation promotion, limb warmth, lightness of foot, and coldness in limbs. Daily bathing with S bath additive for 15 days significantly improved all symptoms compared with bathing in plain water. A comparison between single and daily bathing with S bath additive showed that relieving fatigue and lumbago were significantly improved after consecutive bathing, demonstrating the benefits of long-term usage. Discussion: Bathing once with S bath additive had acute effects on symptoms associated with peripheral circulation, such as coldness in limbs, body warmth, and limb warmth. Daily bathing with S bath additive improved bone- and joint-related symptoms, such as lumbago and shoulder stiffness, demonstrating that the chronic effects of S bath additive differ from the acute ones. These results are consistent with previous studies on natural hot springs which found that the efficacy of short-term treatment was distinct from that obtained after >2 weeks of treatment.

Design : A pilot, comparative study was conducted. Background : Heat wraps using bentonite (HWb) are commonly used in thermotherapy. In the Okayama University Misasa Medical Center, heat wraps using mud (HWm) produced by mixing soil with boiling water have also been used. The subjective thermal effects of HWm on patients with osteoarthritis of the knee have been reported. However, the objective thermal effects of HWm have not been examined. As such, the physicochemical thermal effects of HWm were analyzed and compared with those of HMb. Methods : The thermal effects of HWm and HWb were investigated regarding heat radiation, conduction, capacity and moisture content. Heat radiation and conduction were measured by changes in temperature of the heat wraps, in addition heat conduction was also assessed by blood flow in body surfaces (N=7). Heat capacity and moisture content were measured with a Differential Scanning Calorimeter. Results: Heat radiation and heat conduction of HWm were significantly greater than those of HWb (p<0.001). The specific heat capacity of HWm was 2.0 J/g/°C, and was 1.7 J/g/°C for HWb. Moisture content of HWm and HWb were 0.6 mg/g and 0.3 mg/g, respectively. Conclusion : Heat radiation, conduction and capacity of HWm are superior to those of HWb. Moreover, the moisture content in HWm is greater than that of HWb. These results indicate that the thermal effects of HWm would have more be physicochemical usefulness.

Our previous studies have shown that spa therapy can reduce subjective symptoms and improve ventilatory function in patients with chronic obstructive pulmonary disease (COPD). The aim of this study is to measure the effects of spa therapy on walking distance during the six-minute walk test in patients with COPD. Twenty-five COPD patients hospitalized for pulmonary rehabilitation at our hospital were included in this study. Twenty-two patients were male and 3 patients were female. Two patients had stage I, 9 patients had stage II, and 14 patients had stage III COPD, according to the Global Initiative for Chronic Obstructive Lung Disease. We offered complex spa therapy (swimming training in a hot spring pool, inhalation of iodine salt solution, and fango therapy) in all patients for 4 weeks. Ventilatory function, six-minute walk distance, oxygen saturation and Borg scale were measured. Vital capacity (VC) was significantly improved by spa therapy at 4 weeks (p<0.05). The values of forced vital capacity (FVC), forced expiratory volume in one second (FEV_1.0), forced expiratory flow after 75% of expired FVC (FEF₇₅), forced expiratory flow after 50% of expired FVC (FEF₅₀), forced expiratory flow after 25% of expired FVC (FEF₂₅), mean expiratory flow during the middle half of the FVC (FEF_25-75), residual volume (RV), functional residual capacity (FRC), peak expiratory flow (PEF) and diffusing capacity for carbon monoxide (DLco) showed a tendency to increase, however the increase in the 10 parameters was not significant. The values of six-minute walk distance before and after spa therapy were 288±106m and 323±114m, respectively (p<0.05). There was a significant decrease in values of maximum Borg Scale values (p<0.05). The values of minimum oxygen saturation and the values of oxygen saturation at rest slightly increased, but not significantly. The change of six-minute walk distance correlated with change of VC (r=0.545; p<0.05), with change of FVC (r=0.628; p<0.05), with change of FEV_1.0 (r=0.559; p<0.05), with change of FEF₅₀ (r=0.480; p<0.05), with change of minimum oxygen saturation (SpO₂) (r=0.554; p<0.05) and with change of SpO₂ at rest (r=0.445; p<0.05). We found that spa therapy induced improvements in ventilatory dysfunction and six-minute walk distance in patients with COPD. The results from this study reveal that spa therapy may improve disease control and exercise tolerance in patients with COPD.