Correlation between pupillary size and heart rate variability parameters among medical students

Abstract

Autonomic nervous system controls and balances sympathetic and parasympathetic system to maintain homeostasis without conscious control. The sympathetic nervous system controls the dilation of the pupil or mydriasis. HR variation (HRV) analysis is a popular non-invasive tool for assessing functions of autonomic nervous system. Medical students are under constant cognitive load, it is required to follow-up on status on their autonomic control during their education phase. The objective of this study was to observe any correlation between pupillary size and heart rate.Total of 30 students participated in the study. Anthropometric measurements and vitals like pulse, blood pressure was recorded. Pupillary size of the participants was measured using the pupillometer in the illuminated. HRV recording was done by placing electrodes for standard Lead II ECG. HRV reports were generated using Kubios HRV 3.5 software standard version. The pupillary size Right and Left are negatively correlated with the SDNN, RMSSD, PNN50, HF, SDI and SD2. However, LF, LF/HF and SD2/SD1 ratio are positively correlated. These findings support the notion that pupillary size can serve as a non-invasive indicator of autonomic nervous system activity.