Wavelet analysis of heart rate variability during microgravity simulation

Abstract

Lately, heart rate variability (HRV) and blood pressure adaptations have been studied in relation to Space Exploration. Most data obtained so far, indicate a decrease in heart rate (HR), mainly explained by a decrease in the low frequency component (LF) of HRV and an increase in the high frequency band (HF), indicating a predominant vagal modulation during space flights. In order to validate our laboratory and in-house analysis software, as potential tools for space life sciences, 14 normal subjects participated in a 2 hours protocol of simulated weightlessness (HDT-6o) in addition to a Mental Stress Maneuver. All cardiac components were collected, and after wavelets analysis, preliminary results show a significant decrease in HR (p=0,0128). The LF/HF ratio shows a clear tendency to decrease, with a comprehensible increase in HF. During Mental Stress, HR was increased, correlating with higher LF, alongside a general decrease in HF. Overall, our preliminary results validate our laboratory, for studies in the field of human space physiology.