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Related Experiment Video

Updated: May 8, 2025

Calculating Heart Rate Variability from ECG Data from Youth with Cerebral Palsy During Active Video Game Sessions
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Exercise Heart Rate Variability Suggests Parasympathetic Hyperactivity during Simulated Military Operations

Adam C Lowe1, Alexandra Niclou, Alyssa N Varanoske2

  • 1Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA.

Medicine and Science in Sports and Exercise
|April 25, 2025
PubMed
Summary
This summary is machine-generated.

Testosterone supplementation did not negatively impact heart rate variability (HRV) during simulated military operations. Exercise HRV metrics indicated parasympathetic hyperactivity despite increased stress, suggesting testosterone maintains autonomic balance in physically active males.

Keywords:
AUTONOMIC NERVOUS SYSTEMEXERCISEHEART RATE VARIABILITYMULTISTRESSOROPS II

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Area of Science:

  • Exercise physiology
  • Autonomic nervous system function
  • Endocrinology

Background:

  • Heart rate variability (HRV) measures autonomic balance and is sensitive to stress.
  • Testosterone may preserve cardiac autonomic tone during strenuous activity.
  • Assessing exercise HRV during simulated military operations can reveal physiological and psychological stress responses.

Purpose of the Study:

  • To evaluate exercise heart rate variability (HRV) as a stress marker.
  • To determine if testosterone administration maintains HRV during prolonged simulated military operations.

Main Methods:

  • Thirty-two physically active males participated in a 20-day simulated military operation study.
  • Participants received either testosterone undecanoate or a placebo.
  • Exercise HRV was measured during load carriage exercise, analyzing metrics like SDNN, RMSSD, LF, HF, and LF/HF.

Main Results:

  • Heart rate variability (HRV) metrics (SDNN, RMSSD, LF, HF) increased over the study period under both low-stress and high-stress conditions.
  • The low-frequency to high-frequency ratio (LF/HF) remained unchanged throughout the operations.
  • Testosterone administration resulted in a higher LF/HF ratio compared to placebo during both low-stress and high-stress days.

Conclusions:

  • Exercise HRV indicated parasympathetic hyperactivity despite escalating stress during simulated military operations.
  • A single dose of testosterone undecanoate did not adversely affect the autonomic response to high stress in healthy, active males.