What is the Origin of High Frequency Power Index?

This term is a standard metric within the field of psychophysiology and autonomic nervous system research, stemming from the application of spectral analysis (Fourier transformation) to the continuous measurement of heart rate intervals. The recognition of the high-frequency component's link to respiration and vagal outflow was a critical development in non-invasive autonomic assessment. It has become a key tool for quantifying the rest-and-digest response.

What is the Mechanism of High Frequency Power Index?

The high-frequency oscillations in heart rate are primarily driven by the respiratory modulation of vagal efferent activity to the sinoatrial node of the heart, a phenomenon known as Respiratory Sinus Arrhythmia. During exhalation, vagal activity increases, slowing the heart rate, while during inhalation, it decreases. The HF Power Index measures the magnitude of this fluctuation, directly reflecting the parasympathetic system's capacity to exert its regulatory influence and maintain cardiovascular stability.

High Frequency Power Index ∞ Area

High Frequency Power Index

Meaning

The High Frequency Power Index (HF Power) is a specific component of Heart Rate Variability (HRV) analysis, representing the absolute or relative power in the high-frequency band of the heart rate spectrum, typically corresponding to respiratory frequencies. This index serves as a quantitative, non-invasive metric of parasympathetic nervous system activity, reflecting the strength of vagal tone. A higher HF Power Index is generally correlated with greater cardiac health, superior emotional regulation, and enhanced physiological resilience.