Heart rate responses induced by acoustic tempo and its interaction with basal heart rate

Figures

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  Figure 1. Correlation between individual HR and change in HR. (A) Experimental procedure for Experiment 1. The experimental procedure consisted of two periods and a 1-min rest: baseline period (5 min) → 1-min rest → condition period (5 min). (B) The horizontal axis indicates the individual HR, which is the average HR in baseline recording. The vertical axis indicates the change in HR, which is the average HR obtained during condition period recording. Each point represents the data set of one participant. Since the participants listened to the sound at 80 BPM in the condition period, the vertical line is drawn on the graph at 80 BPM. The diagonal line and equation indicate an approximately straight line and the approximation formula, respectively.

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  Figure 2. Normalized mean HR, lnHF and lnLF/HF of each condition in Experiment 2. (A) Procedure for Experiment 2. (B) The equation and an example of Experiment 2. The graph represents the time-series data of the HR of a participant. The solid blue line represents the tempo of sound in this condition (x = 15). (C) The vertical axis indicates the normalized mean HR (percent of baseline of each session). (D) The vertical axis indicates the normalized lnHF of the HRV (percent of baseline of each session). (E) The vertical axis indicates the normalized lnLF/lnHF ratio of the HRV (percent of baseline of each session). The horizontal axis indicates the condition number shown in Table 2. The acoustic tempo increases from left to right. The bar graphs and error bars represent the mean ± SEM. Statistical significance is indicated as *p < 0.05, **p < 0.01, ***p < 0.001 from the baseline. The trend of the increase is indicated as †p < 0.1 compared with the baseline.

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  Figure 3. Time series of average HRs of all participants in Experiment 3. (A) Procedure for Experiment 2. (B) The equation and an example of Experiment 2. The graph represents the time-series data of the HR of a participant. The solid blue line represents the tempo of sound in this condition (x = 2). (C) The definitions of M1-M5, and T1-T5. The mean HRs of the 1-min windows were defined as M1, M2, M3, M4 and M5 in 5-min condition periods, and the corresponding 1-min time regions were defined as T1, T2, T3, T4, and T5, respectively.

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  Figure 4. Time series of average HRs of all participants in Experiment 3. The data are normalized by the basal HR in the baseline recording. Each graph represents the time series HRs under each condition shown in Table 2. The vertical axis indicates the normalized mean HR (percent of baseline of each session). The horizontal axis indicates the time after the presentation of the sound stimuli. The rate of increase of the acoustic tempo per minute is indicated in each graph. The blue solid line represents the sound tempo normalized by the start of the acoustic tempo. The red box represents the mean value (center line) and SEM (top and bottom line). Statistical significance is indicated as †p < 0.05, ††p < 0.01, †††p < 0.001 from the baseline.

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  Figure 5. Mean HRs of the 1-min windows in Experiment 3. The data are normalized by the basal HR in the baseline recording. Each graph represents the mean HRs of the 1-min windows shown in Fig. 3C. The vertical axis indicates the normalized mean HR (percent of baseline of each session). The horizontal axis indicates the condition number shown in Table 2. The rate of increase in the acoustic tempo per minute is 0%/min, 1%/min, 2%/min, 3%/min and 4%/min, from left to right, respectively. The bar graphs and error bars represent the mean ± SEM. Statistical significance is indicated as *p < 0.05, **p < 0.01, ***p < 0.001.

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  Figure 6. Normalized lnHF and lnLF/lnHF of HRV of each condition in Experiment 3. The horizontal axis indicates the condition number shown in Table 2. The acoustic tempo increases from left to right. (A) The vertical axis indicates the normalized lnHF of the HRV (percent of baseline of each session). (B) The vertical axis indicates the normalized lnLF/lnHF ratio of the HRV (percent of baseline of each session). The bar graphs and error bars represent the mean ± SEM. Statistical significance is indicated as **p < 0.01 from the baseline.