Abstract
In recent years, water massage bed for full body massage has been used in physiotherapy effectively. Compared with other physiotherapy equipment, water massage bed is particularly useful since it can directly massage the destined area on the subject, which leads to improvement in relieving muscle strain and provides a psychological relaxation. In this study, we use a heart rate sensor as well as an accelerometer and a laser range finder to measure and evaluate changes of relaxation in the human body before and during the massage. As a result, the water massage bed vibrations observed concentrated at 4Hz or less. We observed that subjective evaluation is strongly correlated to the heart rate based relaxation analysis and subjects' weight. In addition, the result of the subjective evaluation is influenced by the changes in autonomic nerve activity in the first 30 seconds of the massage.