Methods for Heart Rate Variability Biofeedback (HRVB): A Systematic Review and Guidelines

Abstract

Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual’s resonance frequency, which stimulates respiratory sinus arrhythmia (RSA) and the baroreflex. There is, however, no methodological consensus on how to apply HRVB, while details about the protocol used are often not well reported. Thus, the objectives of this systematic review are to describe the different HRVB protocols and detect methodological concerns. PsycINFO, CINALH, Medline and Web of Science were searched between 2000 and April 2021. Data extraction and quality assessment were based on PRISMA guidelines. A total of 143 studies were finally included from any scientific field and any type of sample. Three protocols for HRVB were found: (i) “Optimal RF” (n = 37), each participant breathes at their previously detected RF; (ii) “Individual RF” (n = 48), each participant follows a biofeedback device that shows the optimal breathing rate based on cardiovascular data in real time, and (iii) “Preset-pace RF” (n = 51), all participants breathe at the same rate rate, usually 6 breaths/minute. In addition, we found several methodological differences for applying HRVB in terms of number of weeks, duration of breathing or combination of laboratory and home sessions. Remarkably, almost 2/3 of the studies did not report enough information to replicate the HRVB protocol in terms of breathing duration, inhalation/exhalation ratio, breathing control or body position. Methodological guidelines and a checklist are proposed to enhance the methodological quality of future HRVB studies and increase the information reported.

A Pilot Feasibility Evaluation of a Heart Rate Variability Biofeedback App to Improve Self-Care in COVID-19 Healthcare Workers

“…Since gradual titration helps establish a new behavior, we gave participants the goal of reaching 20 minutes of daily HRVB after 2 weeks. Twenty-minute HRVB sessions are a well-established norm in the eld and a common recommended session length in controlled studies of HRVB (Lalanza et al, 2023). To maximize exibility and reduce likelihood of becoming overwhelmed by a rigid protocol, we gave no further speci cs about how to titrate.…”

“…Recent HRVB protocol guidelines recommend 10-20 minutes of at home HRVB practice on most days (Lalanza et al, 2023); thus, study engagement was de ned a priori as the number of days on which at least 10 minutes of HRVB was completed. We considered the rst recorded HRVB session after the participant completed the 5 pre-intervention HRV readings, no matter the length (often it was only 2 minutes), to mark the beginning date of the intervention.…”

Boosting Heart Rate Variability Biofeedback Adaptability in Cardiac Rehabilitation with Cognitive Model

“…Traditional methods for determining RF have often been limited by speci c laboratory conditions and short-term observations, relying on the expert judgment of therapists. Currently, many studies only conduct a single RF assessment at the outset, with some defaulting to a respiratory rate of 6BPM [22]. Notably, the stability and adaptability of RF throughout continued training remain unde ned [36].…”

“…This breathing method has a relatively smooth breathing waveform and relatively low tidal volume, which cannot achieve the desired training effect. Therefore, some RF-breathing guidelines emphasize the importance of diaphragmatic breathing [22,34]. When participants perform diaphragmatic breathing guided by the airbag, their breathing depth increases and their abdominal circumference changes signi cantly, indicating that they are performing diaphragmatic breathing [44].…”

“…The laboratory training also includes training in diaphragmatic breathing and pursed-lip breathing techniques to ensure achieving the optimal RF without hyperventilation [21]. Therapists analyze patients' physiological signal data, optimize RF settings based on this, and evaluate training effects [22]. Outside of consultation periods, patients maintain daily training sessions of around 20 minutes at home, 4 to 6 days a week, with the entire training cycle typically spanning about four weeks.…”