Heart Rate Variability (HRV) Biofeedback and Athletic Performance: Part Three
In this series of posts, I discuss Heart Rate Variability (HRV) Biofeedback in the context of athletic performance, and in particular:
- Part One: Rationale for using HRV Biofeedback
- Part Two: Important metrics
- Part Three: Common Protocols (this post)
- Part Four: Expected physiological, psychological and performance outcomes
If you are new to HRV Biofeedback, start from part one to learn more about the foundations or part two to learn more about the important metrics to keep track of both during and outside of HRV Biofeedback sessions. Here, we’ll jump right into the most common protocols.
The first standard protocol
HRV Biofeedback has been first formally defined by Lehrer, Vaschillo, and Vaschillo (2000). The authors proposed a protocol consisting of a 10−session program. According to this original protocol, a biofeedback device is needed, which is a device able to display heart rate instantaneously as well as respiration rate, at least in terms of a pacing signal which allows the user to follow a given breathing frequency. The instrument should ideally be available also for home use and not only at the laboratory.
The protocol starts with a first introductory session in which the participant is instructed about how heart rate changes with respiration (e.g. heart rate increasing when breathing in), and how biofeedback can help exercise reflexes in the body and therefore control more efficiently the autonomic nervous system (Lehrer, Vaschillo, and Vaschillo). The participant is informed that sustained practice can help improve health outcomes and manage stress.
During the first session, the resonant frequency of an individual needs to be established. The resonant frequency is typically around 6 breaths/minute, but can change by 0.1–1.5 breaths/minute between individuals. Hence, each participant should try a range of frequencies and the practitioner should determine the optimal frequency by analyzing the power spectrum of each different test. Each test in this phase lasts 3 minutes, and the resonant frequency will be the one with the highest amplitude.
In HRV4Biofeedback, we have introduced a resonant frequency protocol that works similarly, and guides you through a series of breathing frequencies to determine which one is optimal for you, as described here.
At this point, the participant is instructed to practice at home for two 20 minutes periods each day. During the second session, the participant is instructed to look at heart rate and to try to maximize oscillations in heart rate while synchronizing breathing and heart rate. The participant can be instructed about abdominal breathing and pursed lips breathing, and is asked to practice for two 20 minutes sessions per day again. The following eight sessions are mostly used to acquire further experience with the technique. The protocol was used by the same authors in one of the first HRV Biofeedback interventions (Lehrer et al., 2003), where participants were instructed to practice twice per day for 20 minutes, for one week.
The study population, in this case, was not athletes, however I have included the protocol in Table 1 as this is the original protocol employed in most of the following studies on athletes.
Small variations on the original protocol
In Paul, Garg, and Sandhu (2012), a slightly different approach was used. In this case, the protocol was more compact, still providing 10 sessions, but on consecutive days. Each session lasted 20 minutes and included breathing at the athlete’s resonant frequency. The protocol, in this case, was similar to what I have described earlier (Lehrer, Vaschillo, and Vaschillo, 2000; Lehrer et al., 2003), with participants breathing at slightly different frequencies during the first session, so that the resonant frequency could be determined (4.5 to 6.4 breaths/minute). A pacing stimulus was used to aid the process, and the participants were instructed to breathe abdominally and exhale with pursed lips. The same protocol was also used in another study by the same authors (Paul and Garg, 2012). In these studies, no home practice was reported, possibly because of practical reasons.
Another variant of the same protocol was also used by Choudhary, Trivedi, and Choudhary (2016), consisting of a 10-week long intervention where paced breathing was practiced at the athlete’s resonant frequency. The supervised sessions lasted 30–40 minutes including baseline measurements. Additionally, participants were instructed to practice twice per day at home, for 20 minutes each session. Two 20 minutes sessions per day at home plus 10 supervised sessions in the laboratory were also reported in a few other HRV Biofeedback interventions (Lagos et al., 2008, Dziembowska et al., 2016). During these interventions, a standard HRV Biofeedback protocol with deep abdominal breathing following a pacing stimulus was used, as also employed in previous studies (Lehrer, Vaschillo, and Vaschillo, 2000; Lehrer et al., 2003; Paul, Garg, and Sandhu, 2012; Paul and Garg, 2012). Before the intervention, the resonant frequency of each participant was also determined.
Finally, other authors relied on the original protocol but shortened the amount of home-based practice. In one case, the authors used a combined HRV Biofeedback and mindfulness program lasting 10 weeks but with only one 20 minutes session per day (Perry, 2018), while in another study the authors used a rather short 4 weeks intervention comprising of only five 15 minutes sessions per day (Mueller et al., 2019).
A few other studies used different non-standard protocols, often consisting of a single weekly session of varying duration (between 6 and 60 minutes). In particular, HRV Biofeedback was part of a multi-year program targeting Olympic speed-skaters in Canada (Beauchamp, Harvey, and Beauchamp, 2012). While this study included several interventions (psychological skill training or PST, neurofeedback, etc.), HRV Biofeedback was an important element, with weekly sessions of 45 minutes. Weekly sessions were also used in Tanis (2008). The authors administered a protocol which consisted of 30 minutes sessions once per week in supervised settings, combining biofeedback with positive emotional focusing. While the supervised session was 30 minutes, only 5 minutes were used for HRV Biofeedback, and the remaining part of the session was used for baseline measurements and to provide information or feedback on previous sessions. Participants were also encouraged to practice at home, but no data was reported on home use. The intervention lasted 6 weeks.
Two biofeedback interventions with weekly sessions are reported in Perry, Shaw, and Zaichkowsky (2011), one on gymnasts lasting 10 sessions and 5 weeks and one on hockey players and lasting 8 sessions. In the first study, biofeedback was combined with neurofeedback and no details are reported on the exact protocol. The duration of the sessions is reported only for the second intervention, where they lasted 12 minutes. No information is provided on how the biofeedback sessions were delivered, however the authors report a constant breathing frequency of 6 breaths/minute for each athlete, hence it seems that in this case biofeedback was taught in terms of synchronization between heart rate and breathing, but without determining the optimal resonance frequency for each athlete. Short weekly sessions were also reported in another intervention, where they lasted 10 minutes for 6 weeks (Wakefield and Shipherd, 2017).
On the opposite side of the spectrum, either very long weekly sessions or very short multiple times per day sessions have been proposed in a few studies. Biofeedback was combined with neurofeedback in Dupee and Werthner (2011), where the authors report 60 to 90 minutes sessions, for a total of 20–40 hours per athlete. In this case, paced breathing lasted between 6 and 20 minutes, and it increased over time. Similarly, Pusenjak et al. (2015) used an 8-week intervention with two one hour sessions each week. It is unclear what were the specifics of these sessions in terms of biofeedback and instructions to the participants. However, the authors report asking the participants to perform breathing exercises at home (without using a device, in my understanding). On the other hand, Rijken et al. (2016), used a home-based protocol with daily sessions and guided paced breathing. The intervention lasted 5 weeks and consisted of about three daily sessions as short as 3 minutes, for an average of 100 sessions per athlete.
Similarly, Deschodt-Arsac et al. (2018) used a 5 weeks protocol with two sessions per day of 5 minutes in duration.
HRV Biofeedback protocols considerations
While most protocols, especially in the early days, consisted of supervised sessions in laboratory settings (Perry, Shaw, and Zaichkowsky, 2011; Beauchamp, Harvey, and Beauchamp, 2012; Pusenjak et al., 2015), there is a tendency in doing more home-based unsupervised practice in recent studies (Rijken et al., 2016; Perry, 2018; Mueller et al., 2019).
The only formally defined protocol for HRV Biofeedback (Lehrer, Vaschillo, and Vaschillo, 2000) includes both supervised sessions once per week and daily practice at home, and can therefore benefit in terms of practical applicability from recent advancements in technology (e.g. availability of smartphone apps for HRV Biofeedback).
Considering these factors, and the demands of modern-day life, small variations of the original protocol that require less time from the athlete (from 3 to 20 minutes instead of two sessions of 20 minutes per day) are currently more often considered by researchers and practitioners working in applied settings (Rijken et al., 2016; Perry, 2018; Deschodt-Arsac et al., 2018; Mueller et al., 2019).
In the last post of this series, we’ll see what are the expected physiological, psychological and performance outcomes in athletes, based on published literature using the protocols and methods described so far.
Marco holds a PhD cum laude in applied machine learning, a M.Sc. cum laude in computer science engineering, and a M.Sc. cum laude in human movement sciences and high-performance coaching.
He has published more than 50 papers and patents at the intersection between physiology, health, technology and human performance.