The influence of biofeedback on respiratory training effect

Clinical studies have indicated that some diseases such as insomnia, anxiety, and minor melancholia all have close correlation with autonomic nervous system. The respiratory training can regulate the function of human autonomic nervous system and consequently release stress. We design a respiratory training biofeedback system which trains the subjects to perform pursed lips abdominal breathing and provide audio and visual biofeedback to them. The audio biofeedback is a pure tone and the visual biofeedback is a graphic blue bar. The frequency of pure tone and height of graphic bar are all regulated by the ratio of low frequency and high frequency components of heart rate variability (LF/HF ratio) which is considered as one indicator of autonomic nervous system activity. This paper assesses the influence of biofeedback on the respiratory training effect by comparing the variation of LF/HF ratio during respiratory training using or not using biofeedback. The results indicate that biofeedback has significant influence on the respiratory training effect but the influence shows individual variability. The visual biofeedback seems to show more significant influence than audio biofeedback.