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Dr. Donald Moss's Ethical Principles and Practice Standards in Clinical Biofeedback (BCIA-aligned, 3 APA CE credits) 

Registration Link: https://www.optimalhrv.com/event-details-registration/master-ethical-principles-practice-standards-in-clinical-biofeedback-aligned-with-bcia

This week we cover five studies that stretch heart rate variability into some surprising territory. We start with elite wrestlers and what heart rate variability reveals about training recovery, move into the modern office to look at heart rate variability as an objective marker of musculoskeletal pain risk, and head into neurology for two studies on seizure diagnosis and unexplained neurological symptoms. We close with a study on sound your ears can't consciously hear, but your nervous system apparently can.

RESEARCH HIGHLIGHTS THIS WEEK

1. Investigating the Acute Effect of Different Training Protocols on Heart Rate Variability

PUBLICATION: Sports

AUTHORS: Burhan Demirkıran, Tuba Melekoğlu, Grzegorz Żurek

KEY FINDING:

In thirteen elite Greco-Roman wrestlers, both high-intensity interval training and prolonged endurance training produced dramatic acute suppression of heart rate variability, with SDNN dropping seventy-three to eighty-two percent immediately after exercise, followed by partial recovery at the twenty-four-hour mark. After correcting for multiple comparisons, there was no statistically significant difference between the two training protocols.

SIGNIFICANCE:

Coaches often assume that different training modalities carry meaningfully different acute costs to the nervous system, but this study suggests that intense effort of either type may impose a comparable autonomic burden, at least in this population and time frame. That has real implications for how training loads are planned in the days leading up to competition.

Read full study: https://www.mdpi.com/2075-4663/14/7/299

2. Heart Rate Variability as an Objective Biomarker for Work-Related Musculoskeletal Disorder Risk: A Cross-Sectional Study of Hong Kong (China) Professionals

PUBLICATION: Exploration of Musculoskeletal Diseases

AUTHORS: Adrian Low, Benny Lam

KEY FINDING:

In 105 Hong Kong office professionals, lower heart rate variability coherence was associated with higher musculoskeletal pain intensity and a broader spread of pain across the body, even after accounting for self-reported stress. Forward head posture and thoracic kyphosis helped explain part of the relationship between coherence and neck and shoulder pain, and daily sedentary hours changed the strength of the overall association.

SIGNIFICANCE:

This cross-sectional study points to heart rate variability coherence as a promising objective physiological signal of musculoskeletal risk, distinct from self-reported stress, with posture and sedentary behavior as concrete, modifiable intervention targets worth testing in future longitudinal research.

Read full study: https://www.explorationpub.com/Journals/emd/Article/1007128

3. Preictal Reduction in Heart Rate Variability Entropy Is Associated With Functional/Dissociative Seizures and Provides Modest Discrimination From Epileptic Seizures

PUBLICATION: Epilepsy and Behavior

AUTHORS: Hesam Shokouh Alaei, Rohan Kandasamy, Samaneh Kouchaki, Mahinda Yogarajah, Daniel Abasolo

KEY FINDING:

Among one hundred and twenty-five patients undergoing video monitoring, heart rate variability entropy dropped meaningfully in the period just before functional or dissociative seizures, but not before epileptic seizures. A machine learning model built on this signal achieved 73.5% sensitivity and 61.9% specificity in distinguishing the two seizure types.

SIGNIFICANCE:

This is an early but promising step toward a lower-burden, electrocardiogram-based tool that could one day help triage patients toward the seizure-type-specific care they need, though the authors are clear that accuracy is not yet high enough to replace video electroencephalography monitoring on its own.

Read full study: https://www.sciencedirect.com/science/article/abs/pii/S1525505026003021

4. Integrated Electrocardiography-Heart Rate Variability Analysis in Neurologically Symptomatic Individuals Without Cardiac Symptoms: A Data-Driven Retrospective Observational Study of Electrocardiographic-Autonomic Associations

PUBLICATION: Cureus

AUTHORS: Manju Lata, Manoharan Renugasundari, Gagan K. Banodhe, Md Zabihullah, Tribhuwan Kumar

KEY FINDING:

In a retrospective analysis of three hundred and fourteen neurologically symptomatic patients without cardiac symptoms, most commonly presenting with dizziness, headache or migraine, and hyperhidrosis, standard electrocardiogram conduction and repolarization measures were largely normal, but heart rate variability analysis revealed subtle autonomic dysregulation compared to normative values.

SIGNIFICANCE:

The findings suggest that common neurological complaints may carry an autonomic nervous system component that a standard, symptom-free-looking electrocardiogram would never reveal, positioning heart rate variability as a sensitive complementary tool for early neurocardiac risk detection in this population.

Read full study: https://www.cureus.com/articles/510130-integrated-electrocardiography-heart-rate-variability-ecg-hrv-analysis-in-neurologically-symptomatic-individuals-without-cardiac-symptoms-a-data-driven-retrospective-observational-study-of-electrocardiographic-autonomic-associations

5. Multilevel Physiological Responses to the Hypersonic Effect: Concurrent Electroencephalographic, Heart Rate Variability, and Subjective Evaluation in Healthy Adults in a Participant-Blind Crossover Study

PUBLICATION: Cureus

AUTHORS: Ginji Takasao, Satsuki Okanemasa, Tatsuya Kitagawa, Ichika Shimode, Mari Tarumoto, Kanato Miyatake, Takayuki Kodama, Akio Goda

KEY FINDING:

In a participant-blind crossover study of twenty healthy men, exposure to sound containing inaudible high-frequency components produced a trend-level increase in posterior EEG Alpha-2 activity and a statistically significant reduction in the relative low-frequency component of heart rate variability, compared to audible-only sound, with no difference in subjective ratings between the two conditions.

SIGNIFICANCE:

This suggests a coordinated brain-to-autonomic response to sound content that cannot be consciously perceived, reinforcing the idea that physiological measurement can reveal effects that self-report alone would completely miss.

Read full study: https://www.cureus.com/articles/512115-multilevel-physiological-responses-to-the-hypersonic-effect-concurrent-electroencephalographic-heart-rate-variability-and-subjective-evaluation-in-healthy-adults-in-a-participant-blind-crossover-study

KEY THEMES

SPONSORED BY OPTIMAL HRV

The Optimal HRV app centers on a simple morning measurement protocol, giving you a consistent baseline before daily life adds noise to your numbers. From there, it builds longitudinal tracking over time and includes biofeedback tools to help you train your physiology in the moment.

Learn more about the Optimal HRV app: www.optimalhrv.com

Optimal HRV also supports two continuing education opportunities:

Dr. Inna Khazan's HRV Biofeedback Training (BCIA-aligned, 16 APA CE credits)

Registration Link: https://www.optimalhrv.com/event-details-registration/bcia-aligned-hrv-biofeedback-training-led-by-dr-inna-khazan

Dr. Donald Moss's Ethical Principles and Practice Standards in Clinical Biofeedback (BCIA-aligned, 3 APA CE credits) 

Registration Link: https://www.optimalhrv.com/event-details-registration/master-ethical-principles-practice-standards-in-clinical-biofeedback-aligned-with-bcia