Fig. 4

Mean QTc 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 = 0.0031 resulted after Bonferroni correction (Figure 4 a). Figure 4b shows mean QTc at rest after 4th bicycle ergometry after inhalation of ZnO in different concentrations. No significant differences were detected between exposure conditions (all p values > 0.05). Outliers were defined as in Fig. 1