The mechanism and application of heart rate variability biofeedback regulation of the autonomic nervous system
Wang Hao1, Wang Wendi1, Wu Dongzhe1, Gao Xiaolin1, Shi Yongjin2
1Institute of Sports Science, State General Administration of Sport, Beijing 100061, China; 2Department of Physical Education and Art, China Agricultural University, Beijing 100083, China
Abstract: BACKGROUND: Heart rate variability biofeedback is a respiratory training method that uses slow and deep breathing at the resonant frequency to induce rhythmic, high-amplitude oscillations in the cardiovascular system, thereby stimulating and exercising the autonomic and baroreflex. However, current studies have not systematically reviewed how heart rate variability biofeedback modulates the autonomic function and produces effects. There is a lack of public understanding of the mechanism of heart rate variability biofeedback, and its application progress and scheme are not fully understood.
OBJECTIVE: To review the existing experimental studies on the effects of heart rate variability biofeedback on symptoms in different populations at home and abroad and to introduce the mechanisms and advances in the application of heart rate variability biofeedback to modulate the autonomic nervous system.
METHODS: “Heart rate variability biofeedback, resonance breathing, heart rate variability, autonomic nerve, breathing training, chronic diseases, mental illness, biofeedback” were used as Chinese or English keywords to search in CNKI, WanFang Database, PubMed, and Web of Science. A total of 72 core related papers were included according to the inclusion and exclusion criteria.
RESULTS AND CONCLUSION: The body’s oscillation system and resonance system are essential for the effectiveness of heart rate variability biofeedback. Oscillations reflect the response to external stimuli and self-regulating reflex systems, while resonances involve synchronous oscillations that result in higher amplitude operations. The balance between sympathetic and parasympathetic nerves is crucial for maintaining a stable internal environment. Autonomic nervous system disorders are associated with reduced heart rate variability and are closely linked to the progression of related diseases. Heart rate variability biofeedback utilizes the resonance characteristics of the cardiovascular system, inducing rhythmic high-amplitude oscillations by employing deep slow breathing at the resonance frequency. This method improves the regulatory function of the sympathetic and parasympathetic system reflexes and enhances the balance regulation between the two systems. Two major mechanisms of cardiovascular system resonance are the baroreflex closed-loop pathway and respiratory sinus arrhythmia. These mechanisms, along with the unique delay of baroreflex, result in a 0° phase angle oscillation between heart rate and respiration and a 180° phase angle oscillation between blood pressure and respiration during breathing at the resonant frequency rhythm. Periodically stimulating the human cardiovascular oscillation system through this method is an easy-to-operate and effective training approach. Currently, heart rate variability biofeedback is mainly applied in the fields of mental illness, chronic disease, and sports. However, the intervention mechanism and efficacy are unclear, the intervention content, frequency and duration are varied, and there are limited review studies on the intervention methods tailored to different types of individuals. As a non-drug and non-invasive intervention, heart rate variability biofeedback can significantly increase heart rate variability, regulate the balance between sympathetic and parasympathetic nerves, and improve the stability and adaptability of the autonomic nervous system. In the future, it is suggested to investigate the mechanisms and potential applications of the pathways of the heart rate variability biofeedback that induce cardiovascular resonance. It is also recommended to incorporate long-term follow-ups to assess the sustained value of heart rate variability biofeedback in various fields. This would provide new directions and strategies for the comprehensive treatment of complex diseases.
Key words: heart rate variability biofeedback, resonant breathing, autonomic nervous system, heart rate variability, biofeedback, respiratory training, slow breathing, stress, physical and mental health, regulation of physiology