The effect of breathing exercise on hemodynamics and heart rate variability parameters in hypertensive patients: A systematic review.

Several types of breathing exercise (BE) have demonstrated effect on hemodynamics and heart rate variability (HRV) parameters in hypertension (HT). However, the effectiveness of each breathing pattern requires greater study. The purpose of this review is to explore the benefits of BE in hypertensive patients. Randomized controlled trials (RCTs) and clinical trials were retrieved from six electronic databases (PubMed, ScienceDirect, Web of Science, Scopus, ProQuest, and Cochrane Library). The risk of bias and quality of evidence was assessed using the modified Downs and Black checklist and the GRADE approach, respectively. Eight RCTs and three clinical trials were included in this review. All studies were high-quality studies, comprising four breathing groups: deep and slow breathing, manipulated nostril breathing, cycle of breathing, and prolonged expiration breathing. The findings suggest low to high-quality evidence for the effectiveness of four subgroups of BE. When stratified by outcome, the level of evidence on the benefit of BE was low to moderate on attenuating systolic blood pressure (SBP) and diastolic blood pressure (DBP). The evidence for heart rate (HR) reduction was low to high. Furthermore, there was moderate-quality evidence on lowering mean arterial blood pressure (MAP) and modulating HRV parameters. In conclusion, BE elicits a positive effect on hemodynamics and HRV parameters in hypertensive patients.