Background and purpose : Health is characterized by variability, and the loss of variability is associated with aging and disease. Normal healthy respiratory patterns are characterized by breath to breath variability. Cold-Heat scores are quantified indices in Korean Medicine. The aim of this study is to analyze relations between 9 respiratory indices (including breath to breath variability) and HRV(heart rate variability). Method : Respiratory data were measured during a period of 15 minutes and transferred to text file. We calculated 9 respiratory parameters using MATLAB 7.1. Afterwards we did correlation analysis of the 9 respiratory indices and HRV. Results and conclusion : Respiratory variability showed significant correlation with HRV.