Applying Heart Rate Variability to Monitor Health and Performance in Tactical Personnel: A Narrative Review

Figures

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  Figure 1. Example layout of the relations between various organs throughout the body and the Autonomic Nervous System.

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  Figure 2. Example of R-R intervals in milliseconds (duration between R peaks from consecutive QRS complexes). Trace 2 (lower, in red) shows little/negligible heart rate variability (HRV). Trace 1 (upper, in blue) shows significant HRV. Data table on right exemplifies importance: average heart rate (HR as bpm) is identical, but when the underlying signal is teased apart, massive differences in root mean squared of successive differences (RMSSD ~ 17 fold) and can be used to infer significant differences in autonomic nervous system (ANS) resource allocation between the same samples.

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  Figure 3. Opportunities within tactical populations for heart rate variability (HRV) collection throughout the day. Pre-sleep HRV assessments inform end of day status, daily resource consumption, and can quantify daily workload. During sleep, HRV provides insight on nocturnal recovery, homeostatic restoration, and daily readiness. Pre- and post-training HRV spot checks may inform acute preparedness for and recovery from training. During events, HRV can provide insights on performance workload and efficiency.

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  Figure 4. Example of daily heart rate variability (HRV) monitoring of a single individual using a rolling 28-day average to calculate daily Z-scores. Reduced root mean square of the differences in adjacent N-N intervals (rMSSD) and the respective Z-score values below 0 may suggest incomplete recovery, while Z-score values at or above 0 may suggest complete recovery status.