Fig. 3From: Heart rate variability and cardiac repolarization after exposure to zinc oxide nanoparticles in healthy adultsLF power (a), HF power (b) and LF/HF-ratio (c) according to ZnO concentrations and time points. Differences between before exposures and the different time points with a significance level of p < 0.05 are indicated. A significance level of α = 0.0042 resulted after Bonferroni correction. Outliers were defined as in Fig. 1Back to article page