A relaxation system adapting to user´s condition-identification of relationship between massage intensity and heart rate variability

The purpose of the study is to build a relaxation system which can control a user´s body condition, changing the operation mode and intensity of the massage seat according to the user´s current condition. Heart rate is an index of human conditions which can be easily measured, and it has chaotic dynamics. We show relations between the intensity of the massage operation and two indices which express chaotic properties such as correlation dimension and Lyapunov exponent. These data are indispensable for building a feedback loop between the relaxation system and a user.