Globally chaotic analysis of Heart Rate Variability during acute auditory stimulus by heavy metal music

OBJECTIVE: Auditory stimulation with relaxing style music can improve cardiac autonomic regulation in subjects treated with a cardio-toxic medication. We assess the acute effect of heavy metal music on cardiac autonomic regulation, through novel high spectral chaotic global analysis techniques: (a) high spectral detrended fluctuation, (b) high spectral entropy (c) spectral multi-taper method. METHOD: We investigated young adult women between 18 and 30 years old exposed to heavy metal (75-84 dB) music for 20 min. Normality tests were applied: (i) Anderson-Darling, (ii) Ryan-Joiner (similar to Shapiro-Wilk); (iii) Lilliefors for low number of subjects. They all indicated a non-normal data distribution. Consequently we applied the Kruskal-Wallis non-parametric test. Also because of the small population, we used a broader than usual level of significance (critical p = 0.1). RESULTS: The application of the three tests for normality and the non-parametric test of significance by the KruskalWallis technique showed that acute musical auditory stimulation with heavy metal music lead to a significant increase (p < 0.07) in one of the seven combinations of chaotic globals. The most significant combination of chaotic globals is the Chaos Forward Parameter One (CFP1), which includes all three studied chaotic globals (high spectral detrended fluctuation, high spectral entropy, spectral multi-taper method). We found significantly increased values during musical auditory stimulation for this specific CFP1. CONLCUSION: It is suggested that acute musical stimulation with heavy metal influences cardiac autonomic regulation at a more complex level than previously reported and that this may be beneficial to heart function.