Stress-Relieving Effects of Short-Term Balneotherapy - a Randomized Controlled Pilot Study in Healthy Adults

Background: Stress-relieving effects of balneotherapy compared to progressive muscle relaxation (PMR) and to resting were investigated by measuring subjective relaxation and salivary cortisol. It was also examined whether participants with a high versus low stress level would have a different relaxation response. Methods: A sample of healthy volunteers was randomized to balneotherapy, PMR, or a resting control group, each intervention lasting for 25 min. Pre-and post-intervention salivary cortisol samples were collected, and participants rated their status of relaxation on a quantitative scale. In addition, 3 questionnaires were applied to detect participants' stress level and bodily complaints. Results: 49 healthy participants were recruited (65.3% female). In a pre-post comparison, salivary cortisol decreased (F = 23.53, p < 0.001) and subjective relaxation ratings increased (F = 132.18, p < 0.001) in all 3 groups. Study participants in the balneotherapy group rated themselves as more relaxed after the intervention as compared to the other groups (F = 5.22, p < 0.009). Participants with a high versus low stress level differed in somatic symptoms and in morning cortisol levels, but showed a similar relaxation response. Conclusion: Findings suggest that compared to PMR and resting, balneotherapy seems to be more beneficial with regard to subjective relaxation effects and similarly beneficial with regard to a decrease in salivary cortisol.