Spectral Analysis of Heart Rate Variability in Student Pilots During Flight Training

Abstract

Spectral analysis techniques are employed to evaluate electrocardiographic signals. The high-frequency (HF) and low-frequency (LF) components of the tachogram reflect autonomic nervous system modulation of heart rate variability (HRV). This study investigated the correlations between successive heartbeats (RR intervals) and these spectral bands to further elucidate autonomic regulation. Student pilots were monitored with Holter electrocardiograms during training missions. Data were analyzed across three phases: 1) before flight operations on ground (bfo), 2) during flight operations (dfo), and 3) after flight operations on ground. RR interval analysis identified three trends during dfo compared to bfo: a decrease (45,1% of students), no change (15,7%), and an increase (39,2%). These patterns were associated with alterations in the correlation indices for LF and HF power. Students demonstrating superior performance (D-Students) exhibited the strongest positive correlation coefficient between RR intervals and LF/HF band power (+58,3%). A similar trend was observed for the correlation between LF and HF power in this group (+2,9%). The findings suggest that a demand for increased cardiac output, typified by decreased RR intervals, is primarily driven by sympathetic activation. A different autonomic state is observed when the heart is already engaged at the onset of a performance challenge. Notably, some individuals establish a new autonomic balance at the start of a demanding task, characterized by increased total spectral power and elevated HRV, indicative of an optimized autonomic state under high-load conditions.