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Biofeedback
Volume 36, Issue 3, pp. 109–115
©Association for Applied Psychophysiology & Biofeedback
www.aapb.org
Biofeedback Fall 2008
109
FEATURE
Heart Rate Variability Biofeedback as a Strategy for
Dealing with Competitive Anxiety: A Case Study
Leah Lagos,1 Evgeny Vaschillo,1 Bronya Vaschillo,1 Paul Lehrer,2 Marsha Bates,1 and Robert Pandina1
1
Center of Alcohol Studies, Rutgers, The State University of New Jersey, New Brunswick, NJ; 2University of Medicine and Dentistry of New Jersey,
Department of Psychiatry, Piscataway, NJ
Keywords: biofeedback, heart rate variability, golf, competitive stress, optimal performance
Heart rate variability (HRV) biofeedback (BFB) is a relatively
new approach for helping athletes to regulate competitive
stress. To investigate this phenomenon further, a qualitative
case study examined the impact of HRV BFB on the mood,
physiology, and sport performance of a 14-year-old golfer.
The golfer met once per week at a university lab for 10
consecutive sessions of HRV BFB training that included
breathing at a frequency of 0.1 Hz. The format and duration of
sessions followed the HRV BFB protocol outlined previously
by Lehrer, Vaschillo, and Vaschillo. Acute increases in total
HRV, low-frequency HRV, and amplitude of oscillation at
0.1 Hz were observed during biofeedback practice. This
effect became stronger across sessions, suggesting increases
in baroreflex gain. Following HRV BFB, the golfer achieved
his personal record score for 18 holes of golf, and his mean
golf score (total number of shots per 18 holes of golf) was
15 shots lower than in his previous golf season. The golfer
received no golf instructions during HRV BFB training. The
results of this case study suggest that HRV BFB training
may help the athlete cope with the stress of competition
and/or improve neuromuscular function.
Introduction
The term “heart rate variability” (HRV) refers to a measure
of the beat-to-beat changes in duration of the RR intervals
(RRIs) in the electrocardiogram (ECG). The RRI, or
interbeat interval, is the distance between one R-spike and
the next in the ECG. Psychophysiological models consider
HRV as a measure of the continuous interplay between
sympathetic and parasympathetic influences on heart rate
that yield information about autonomic flexibility and
thereby represent the capacity for regulated emotional
responding (Applehans & Luecken, 2006). The activation of
the sympathetic branch of the autonomic nervous system
(ANS) increases heart rate, while the activation of the
parasympathetic branch, primarily mediated by the vagus
nerve, slows it. Variation in heart rate can be caused by a
variety of factors, including breathing, emotions, and various
physical and behavioral changes. The heart rate changes as
well in response to internal body rhythms, many of which
reflect various homeostatic control systems. In general, high
HRV represents a flexible ANS that is responsive to both
internal and external stimuli and is associated with fast
reactions and adaptability. Diminished HRV, on the other
hand, represents a less transient, less flexible ANS that is
less able to respond to stimuli change (Giardino, Lehrer,
& Feldman, 2000). It follows that HRV may provide a
promising index of an athlete’s ability to respond to both
physical and emotional stress and thus of the capacity to
perform physically at maximal levels.
Strategies for Managing Competitive Stress
A number of stress reduction exercises have been described
in the sport psychology literature to treat child athletes’
symptoms of competitive stress. Studies have dealt with
the influence of relaxation techniques on anxiety in sport,
as well as the integration of cognitive behavioral therapies
to diffuse stress in a number of anxiety-provoking sport
situations, ranging from athletic practice to competition.
The development of mental rehearsal skills has been a staple
of traditional sport psychology interventions (Cummings &
Hall, 2002). The purpose of imagery interventions has been
to reduce state anxiety by familiarizing the athlete with a
specific sport task. Through mental simulation of a stress-
evoking situation in sport, the athlete is believed to get
the “feel” of successful sport-specific motor performances
and reduce precompetitive anxiety. Many protocols call
for athletes to vividly re-create a particular stress-eliciting
situation in their minds and draw attention to the sensation
of stress in the body. Yet the vast majority of such relaxation
techniques aim to relieve the psychophysiological symptoms
of stress rather than address the source of autonomic
imbalance in the body.
Resonance Frequency Breathing
According to Vaschillo, Lehrer, Rishe, and Konstantinov
(2002), the cardiovascular system is characterized by
specific resonance frequencies of HRV that exist at a specific
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frequency for each individual, within the low-frequency
range (0.05–0.15 Hz) of HRV. The spectral distribution
of HRV is organized into conventional frequency ranges
specified by the Task Force of the European Society of
Cardiology and the North American Society of Pacing and
Electrophysiology (1996) and in other consensus papers, for
instance, Berntson et al. (1997). The resonance frequency
for each individual can be detected as the frequency at
which maximum HRV is produced, when the system is
rhythmically stimulated at that frequency. The resonance
frequency in HR for most individuals is close to 0.1 Hz, or
about six cycles per minute.
One ready source of rhythmical stimulation to the
cardiovascular system is respiration. In a phenomenon known
as “respiratory sinus arrhythmia,” vagus nerve activity shows
a rhythmical ebb and flow associated with rate of respiration.
Breathing at about six breaths per minute activates these
resonance properties and induces high-amplitude oscillations
in heart rate at 0.1 Hz. Individual factors such as total blood
volume can render the resonance frequency slightly higher
or lower than 0.1 Hz (six cycles/minute). Resonance in the
cardiovascular system at 0.1 Hz is caused by frequency
characteristics of the heart rate closed loop of the baroreflex
system, through which blood pressure changes are modulated
by changes in heart rate (Vaschillo et al., 2002, 2006).
Breathing at one’s resonance frequency activates and
strengthens the heart rate baroreflex system and thereby
strengthens an important source of ANS modulation
(Giardino et al., 2000; Lehrer et al., 2003). Increased gain in
the baroreflex is found both acutely and chronically after
biofeedback training (Lehrer et al., 2003). HRV biofeedback
(BFB) training appears to bestow a number of benefits to the
system. These include (a) maximizing respiratory efficiency
by making blood more available when oxygen concentration
in the alveoli is at a maximum during inhalation (Giardino
et al., 2000); (b) decreasing hypoxic ventilatory response
while improving oxygen saturation and increasing resistance
to hyperventilation (Bernardi, 2001); (c) increasing the
efficiency of the baroreflexes that indirectly modulate
general emotional reactivity (Lehrer et al., 2003); and (d)
improving the ability of the cardiovascular system to adapt
to circulatory requirements (Landeau, Turcotte, Desagne,
Jobin, & Boulet, 2000). This results in a system-wide energy
efficiency and metabolic energy savings that has been
demonstrated to enhance athletic performance.
Literature Review of HRV BFB and Sports
Applications
Vaschillo and Rishe (1999) and Vaschillo, Visochin, and
Rishe (unpublished data) applied HRV BFB with resonance
frequency breathing at the Lesgaft Sport University in St.
Petersburg, Russia, to 30 elite wrestlers with encouraging
outcomes. The training group, consisting of 15 wrestlers,
performed 20 minutes of HRV BFB twice per day for
10 consecutive days. The control group, consisting of an
additional 15 wrestlers, did not perform respiratory training.
Vaschillo and colleagues found that when athletes breathed
at individual cardiac resonance frequencies, they increased
the amplitude of their heart rate oscillations. In addition,
heart rate decreased (while HRV increased), blood pressure
normalized, and skin temperature increased. Further, the
group trained in HRV BFB demonstrated a reduction in
reaction time, as well as speed of recovery in relaxation
of quadriceps muscles, as compared to no change in the
control group. Through the implementation of HRV BFB,
Vaschillo and colleagues enabled athletes to maintain a state
of autonomic balance marked by a cessation of sympathetic
dominance during competitive challenges.
Strack (2003) also examined the effects of HRV BFB on
high school batting performances in baseball. He reported
that the HRV BFB group improved greater than 60% more
in batting performance than the control group. In addition,
he found that the HRV BFB group demonstrated an increase
in the percentage of total low frequencies in the heart rate
spectrum.
Raymond, Sajid, Parkinson, & Gruzelier (2005) compared
dance performances of 24 Latin and ballroom dancers.
Twenty-four participants from a college dance team were
randomly assigned to an alpha-theta neurofeedback,
HRV BFB, or a no-treatment control condition. Findings
indicated that HRV and neurofeedback improved the
dance performances of individuals as compared to the no-
treatment group. The subscale of timing was increased
by neurofeedback, while the subscale of technique was
increased by HRV BFB.
All three research studies reported HRV BFB as safe with
no side effects. Yet, because of the limited evidence that HRV
BFB can be used to enhance sport performance, the sport and
psychophysiological community may justifiably question
whether these preliminary results can be replicated among
varying populations of athletes. Further research is needed
to evaluate and define the utility of HRV BFB for athletes of
multiple ages, skill levels, and sporting types.
The objective of this case study, therefore, was to evaluate
the utility of HRV BFB as a strategy for reducing competitive
anxiety in a 14-year-old golfer and to encourage further
research in this area. This study was based on the hypothesis
that HRV BFB can be used as a coaching tool for young
athletes to learn how to regulate emotions and improve their
functioning in sports practice, competitions, as well as their
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day-to-day lives. The following information will introduce
the background of the participant, methods, and findings
associated with HRV BFB training. A larger scale study with
collegiate golfers at Rutgers University is underway at our
laboratory.
Background of Participant
The participant in this applied case study was a 14-year-old
competitive golfer beginning his first year of high school
competition. He had played golf since the age of seven,
had been an all-state competitor in elementary and middle
school, and had lived and trained at a golf academy for
the previous two and a half years. During the golf season
prior to HRV BFB training, the participant had maintained
an average score of 91 in an 18-hole golf competition and
an average score of 70 during an 18-hole golf practice. He
attributed this discrepancy to his inability to manage stress
and anxiety during competitions and cited a general fear
of negative social evaluation. He described several panic
episodes marked by shortness of breath, rapid heart rate,
sweating, and fear of losing control while playing in golf
competitions. He experienced similar symptoms during
school exams and when speaking in front of audiences.
Panic attacks did not occur, however, in golf practice. With
his parents’ consent, the golfer sought assistance to improve
his performance in competition from a sport psychology
consultant. During the 10 weeks of HRV BFB training, the
golfer did not receive any professional golf instruction or
training.
Method
Procedure
The 10-week HRV BFB protocol designed by Lehrer,
Vaschillo, and Vaschillo (2000) was implemented with the
participant. The protocol integrated 10 HRV BFB training
sessions that were conducted at a university lab. Each session
lasted 45–60 minutes, included four tasks (A: baseline, B and
C: biofeedback training, and D: baseline) for five minutes
each. Sessions 1, 4, 7, and 10 served as recording sessions.
In the first session, the golfer’s resonance frequency was
defined as 0.1 Hz (Figure 2). ECG and respiration were
recorded during all four tasks. In each recording session,
measures of mood and anxiety were obtained. Sessions 2, 3,
5, 6, 8, and 9 were performed without physiological record.
During sessions the participant was taught to breathe slowly
at his own resonance frequency (but not too deeply) using
abdominal and pursed lips breathing techniques. Also the
participant was asked to engage in two 20-minute breathing
practices each day at home using the “StressEraser” device
(Helicor, New York). The participant submitted a weekly log
of his score per round (e.g., 18 holes) in golf competition to
the experimenter.
Psychological Measures
The Profile of Mood States (POMS): The 65-item POMS
measures six mood states, including anger, confusion,
depression, fatigue, tension, and vigor, and yields one
overall score. The POMS possesses high levels of reliability,
with alpha coefficients from 0.80 to 0.91 (McNair, Lorr,
& Droppleman, 1971). Further, the POMS has been used
extensively in sport psychology research with over 250
sport-related published papers since its introduction (LeUnes
& Burger, 1998).
Because the POMS did not address the full range of
positive mood states that also influence sport performance,
Figure 2. Profile of Mood States (POMS) form. Results on POMS demonstrated
significant improvements in tension, anger, depression, and fatigue through
HRV BFB training.
Figure 1. Participant’s resonance frequency determination. To determine
resonance frequency, the participant was asked to breathe following the pacer
at five frequencies, including 4.5, 5.0, 5.5, 6,0, and 6.5 breaths per minute.
HR and respiration frequency spectra and transfer function (TF) between
respiration as the input and RRIs as the output were calculated separately
for each frequency. The TF was computed as a quotient through dividing HR
spectral power by respiration spectral power at each frequency. Thus, the TF
shows HR response to respiration when participant breathes at each frequency
with the same depth of breathing. Resonance frequency is where the TF is at
the maximal value.
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Fall 2008 Biofeedback
such as confidence and calmness (Hanin, 2000), the
Competitive State Anxiety Inventory (CSAI-2) was used to
assess participants’ affect and cognitions about competition.
Developed by Martin et al. (1990), the CSAI-2 consists of
27-items, each rated on a Likert scale from 1 (“not at all”) to
4 (“very much so”). The 27 items represent three nine-item
subscales, including somatic anxiety, cognitive anxiety, and
self-confidence. Each scale yields a separate score ranging
between 9 and 37. Alpha coefficients ranging between 0.79
and 0.90 demonstrate a high degree of internal consistency
for the CSAI-2 subscales.
Physiological Measures
A J&J Engineering (Poulsbo, WA) I-330 DSP-12 physiograph
unit was used to collect ECG and respiration data. ECG
data were collected at a rate of 500 samples per second. To
measure ECG activity, a negative electrode was attached
to the upper part of the right arm, a positive electrode was
attached to the lower part of the left leg, and a ground
electrode was attached to the upper part of the left arm. To
record respiration, we used two strain gauges: one placed
around the abdomen at the level of the navel, and one at the
level of the upper chest (thoracic placement). As the gauge
stretched, the voltage across the tube changed, and relative
changes in length were measured with a range of 0–100
units of relative strength.
Performance Measures
To measure golf performance, the participant recorded
his weekly score per golf round. This score represents the
number of strokes required to complete 18 holes of golf.
He recorded his weekly golf scores for 10 weeks each sport
season.
Data Analysis
Raw ECG data were analyzed using the WinCPRS software
program (Absolute Alien Oy, Turku, Finland). Beat-to-beat
RRIs were assessed from the ECG signal. A spectral analysis
of RRIs and respiration was performed for each 5-minute
task. Total, low-frequency, and high-frequency HRV indices
were calculated. Cross-spectral analysis was used to calculate
coherence1 between heart rate and respiration curve.
Results
Compared to the first baseline session, changes were found
in affect, physiology, and sport performance following HRV
BFB training.
Affect
The severity of the golfer’s self-reported unpleasant moods
was reduced following HRV BFB. As indicated in Figure 2,
the golfer showed reductions in four out of five negative
mood states between session one and session ten on the
POMS. Notably, he reported a complete absence of tension,
depression, anger, and fatigue after 10 weeks of training.
There was a minimal decrease in vigor, from a score of 14
to a score of 12. There was no reported change in confusion,
which remained at a four. The golfer’s cognitive and somatic
anxiety was also reduced, as measured by the CSAI-2. As
demonstrated in Figure 3, cognitive and somatic anxiety
scores were 14 and 21 in the first session, respectively; the
golfer reported experiencing no cognitive or somatic anxiety
in the final session. Self-reported confidence increased from
a score of 4 to 26 through HRV BFB training. A score of
4 in the initial session indicated that the golfer had lower
confidence than the average high school male athlete (M
= 24.5, SD = 5.52; Competitive Anxiety in Sport, 1990). A
score of 26 in the tenth session demonstrated that the golfer
possessed higher confidence than approximately 50% of
high school male athletes.
Physiology
High-amplitude 0.1Hz oscillations in heart rate, blood
pressure, and vascular tone at the golfer’s resonant
frequency also were elicited during HRV BFB. The phase
shift between HR oscillation and the respiration curve at 0.1
Hz was close to 0°, that is, HR increased during inhalation
and decreased during exhalation (Figure 4). Heart rate
was synchronized with respiration with a coherence equal
1 Cross-spectral coherence assesses the interrelationship and overlap in
spectral properties of two time series. High coherence between respiration
and HRV would occur if a large component of HRV consists of respiratory
sinus arrhythmia. In normal breathing rates, spectral coherence is generally
high in the high-frequency HRV range (0.15–0.4 Hz).
Figure 3. Competitive State Anxiety Inventory (CSAI-2). A comparison between
pre and post scores on the CSAI-2 revealed that the golfer felt markedly less
anxious prior to golf competition and significantly more confident about his
ability to perform.
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to 0.983. Results show that total HRV2 (Figure 5a) and LF
HRV (Figure 5b) considerably increased during HRV BFB
procedure. This effect became stronger across sessions. HF
HRV (Figure 5c) decreased during the HRV BFB procedure
(tasks B and C) in comparison with baseline (tasks A and D),
whereas it considerably increased across sessions. Results
show that total, LF, and HF HRV in baseline (task A and D)
cumulatively were increasing.
Sport Performance
As illustrated in Figure 6, there was a reduction in mean golf
scores after 10 weeks of HRV BFB training. In the season
prior to training, the golfer completed an 18-hole golf
competition in 91 strokes on average; in the season following
training, his mean score decreased to 76 strokes.
Discussion and Future Directions
Training in HRV BFB was followed by large acute and
chronic effects on indices of autonomic function, decreases
in anxiety and various other negative mood states, and
improved athletic performance in this young elite athlete.
The mechanism for emotional and performance effects may
be biofeedback effects on autonomic regulation. HRV BFB
elicits high-amplitude oscillations in the cardiovascular
functions, which in turn train autonomic reflexes (Lehrer et
al., 2003). The increase in LF and total HRV within sessions
reflects resonance effects. The increases in LF HRV at task
A across sessions may reflect increased resting baroreflex
gain. The large increase across sessions at task A in HF HRV
suggests a longer-term increase in vagus nerve activity.
There is evidence that HRV BFB elicits high-amplitude
oscillations in cardiovascular functions, which in turn trains
autonomic reflexes (Lehrer et al., 2003). This training restores
autonomic balance and improves autonomic control that
supports emotional regulation and movement coordination.
2 High-frequency HRV (HF HRV) is defined as the frequency component
from a Fourier analysis between 0.15 and 0.4 Hz. It usually reflects
respiratory sinus arrhythmia, which is mediated by the vagus nerve. Low-
frequency HRV (LF HRV) is the component between 0.05 and 0.15 Hz; it
appears to have both sympathetic and parasympathetic mediation and is
highly correlated with baroreflex activity (Task Force, 1996; Berntson et
al., 1997).
Figure 5. HRV indices across tasks (A, B, C, D) and sessions (1, 4, 7, 10).
Increase of total HRV, LF HRV, and HF HRV indices across sessions supports the
hypothesis that 10 weeks HRV biofeedback training cumulatively activates and
improves autonomic function regulation.
Figure 4. Example of heart rate-respiration synchronization. High synchronization
is an evidence that participant was breathing at resonance frequency.
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Fall 2008 Biofeedback
Future Directions
The golfer’s weekly homework logs indicated regular and
consistent practice for two 20-minute sessions, six days per
week throughout the study. In addition, the golfer reported
implementing breathing skills as needed on the golf course.
We note that the notion that other golfers, or athletes of
any sport type, are able to automatically transfer skills
learned in the laboratory to sport performance is not yet
supported by evidence. According to the deliberate practice
theory, expertise is generated from the development of
domain-specific knowledge structures and skills acquired
through the process of adaptation and practice (Singer and
Janelle, 1999). The development of an automatic process of
resonance breathing may be possible but would likely involve
extensive, massed practice (consistent stimulus-response
mapping) in relevant emotional states and environmental
contexts. Further questions concern how biofeedback skills
should be taught, applied, and practiced in sport.
Future research may also extend beyond the physiological
and psychological domains to include other interesting and
important aspects of young athletes’ lives. Indices such as
substance use, academic grade point average, and number
of skipped sport practices would be important measures to
gauge how the development of self-regulation skills help
define behavioral outcomes.
Caveats and Limitations
It is uncertain whether the immediate training effects of
HRV BFB amplify, decrease, or remain consistent over time.
Longitudinal research is important for several reasons,
the foremost being that researchers lack an understanding
of how long the effects of HRV BFB endure after training
sessions have terminated. Second, individuals learn skills at
different rates, and thus, some athletes may not acquire self-
regulation skills until the tenth session or later. Assessments
of the effects of HRV BFB over durations that exceed 10
weeks are needed, as is research on the utility of booster
HRV BFB sessions following massed training.
Conclusions
The general aim of this study was to demonstrate that HRV
BFB is a viable method of improving golf performance,
perhaps by reducing competitive anxiety. A detailed
understanding of the participant and the psychological,
physiological, and sport performance–related findings were
presented to highlight the utility of this approach for child
athletes. Within this general aim, several aspects of the
methodology were described, including (a) the design of the
study, (b) session format and structure, and (c) measures for
assessing emotional, physiological, and sport performance
changes. Accumulated data suggested that HRV BFB
training may have enhanced the golfer’s ability to cope with
stress and increased his ability to perform optimally during
competition. HRV BFB elicited resonant oscillations in the
cardiovascular system and apparently normalized autonomic
regulation. As such, these techniques may have been
responsible for the substantial improvements in the athlete’s
mood and confidence, reduced the stress he experienced
during competition, and enhanced his golf performance. It
is hoped that the potential benefits of HRV BFB for athletes
of varying ages, skill levels, and sport disciplines undergo
investigation in controlled experimental studies to define
the mechanism(s) of action and advance the development
of outcome measures, strategies, and methods to implement
HRV BFB in sport settings.
Acknowledgment
This study was supported, in part, by NIDA grant P20
DA0 17552.
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Correspondence: Leah Lagos, Center of Alcohol Studies, Rutgers, The State
University of New Jersey, 607 Allison Road, Piscataway, NJ 08854, email:
leahmlagos@gmail.com
Leah Lagos Evgeny Vaschillo Bronya Vaschillo
Paul Lehrer Marsha Bates Robert Pandina
