Abstract
Despite its popularity, little psychological and cognitive science research has investigated sauna bathing, especially among healthy individuals. This study empirically examines the connection between sauna bathing and psychological factors related to bodily sensations and emotional experiences. Two experiments were conducted with healthy subjects. In Study 1, we recruited 180 participants and categorized them into three groups (regular sauna, irregular sauna, and no sauna conditions). The participants were asked to complete an online questionnaire which asked about mindfulness and positive emotions. Study 2 was a field study conducted with 28 participants using a sauna at a spa facility. Before and after bathing, the participants answered a questionnaire similar to that used in Study 1. Twelve participants who took sauna baths and 16 of the participants who did not take sauna baths were included in the analysis. Study 1 showed that sauna bathers had a higher ability of bodily sensory imagery and a higher aesthetic evaluation of haiku poetry. Study 2 showed that sauna bathing increased the observing trait of mindfulness. Although the relationship between sauna bathing and bodily sensations or emotional experiences has been mentioned by sauna users and books, this is the first time that it has been empirically demonstrated. These results are considered to be caused by the increased sensitivity of bodily sensations and the heightened parasympathetic nervous system owing to the high and low temperatures. However, more detailed mechanisms are expected to be elucidated in the future.