Reading silently increased the speed of breathing compared with spontaneous breathing (p < 0.05), while reading aloud and talking shifted respiratory frequency into the low-frequency band.
Do mental and verbal activities affect heart rate variability in healthy volunteers?
Mental and verbal activities significantly alter heart rate variability by changing respiratory frequency, highlighting the need for simultaneous respiratory recording during HRV analysis.
p-value: p=<0.05
OBJECTIVES: To assess whether talking or reading (silently or aloud) could affect heart rate variability (HRV) and to what extent these changes require a simultaneous recording of respiratory activity to be correctly interpreted. BACKGROUND: Sympathetic predominance in the power spectrum obtained from short- and long-term HRV recordings predicts a poor prognosis in a number of cardiac diseases. Heart rate variability is often recorded without measuring respiration; slow breaths might artefactually increase low frequency power in RR interval (RR) and falsely mimic sympathetic activation. METHODS: In 12 healthy volunteers we evaluated the effect of free talking and reading, silently and aloud, on respiration, RR and blood pressure (BP). We also compared spontaneous breathing to controlled breathing and mental arithmetic, silent or aloud. The power in the so called low- (LF) and high-frequency (HF) bands in RR and BP was obtained from autoregressive power spectrum analysis. RESULTS: Compared with spontaneous breathing, reading silently increased the speed of breathing (p < 0.05), decreased mean RR and RR variability and increased BP. Reading aloud, free talking and mental arithmetic aloud shifted the respiratory frequency into the LF band, thus increasing LF% and decreasing HF% to a similar degree in both RR and respiration, with decrease in mean RR but with minor differences in crude RR variability. CONCLUSIONS: Simple mental and verbal activities markedly affect HRV through changes in respiratory frequency. This possibility should be taken into account when analyzing HRV without simultaneous acquisition and analysis of respiration.
Bernardi et al. (2000) studied Healthy (n=12). Mental and verbal activities (talking, reading, mental arithmetic) vs. Spontaneous breathing was evaluated on Heart rate variability (HRV), respiration, and blood pressure (p=<0.05). Reading silently increased the speed of breathing compared with spontaneous breathing (p < 0.05), while reading aloud and talking shifted respiratory frequency into the low-frequency band.