In the present study, the effects of different types of verbal activities on heart rate variability (HRV) were investigated. ECG signals were recorded in ten volunteers during resting (R), reading silently (RS), reading aloud (RA) and talking freely (TF). Time domain, frequency domain and Poincaré plot measures of HRV were calculated for analyzing. Time domain parameter of pNN50, frequency domain parameter of LF (n.u.) and Poincaré plot parameter of SD1/SD2 were found statistically difference in RA and TF compared to R and RS. The results in this study show that HRV decreased while subjects were reading aloud and talking freely. The results also indicated that verbal activities of reading aloud and talking freely improve the sympathetic nervous activity.
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