Sex differences in heart rate and heart rate variability in rats: Implications for translational research

Figures

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  FIGURE 1. Box plots for 24-h values of heart rate (A), inter-beat interval (IBI, (B)), standard deviation of IBIs (SDNN, (C)), root mean square of successive beat-to-beat interval differences (RMSSD, (D)), low frequency power (LF, 0.2–0.75 Hz; (E)), and high frequency power (HF, 0.75–2.5 Hz; (F)), divided by male (n = 87) and female (n = 45) rats. The boxes show the data between the 25th and 75th percentile, the middle line represents the median, the black dot represents the mean. Ln, natural logarithm. Statistics are reported in Table 1.

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  FIGURE 2. The left panel shows a scatterplot of 24-h values of (ln)RMSSD and heart rate as a function of sex. The right panel illustrates the prediction of heart rate values in both sexes at low, mean, and high (ln)RMSSD values. Higher and lower estimates of (ln)RMSSD were derived from ±1SD from the mean. (ln)RMSSD = natural log-transformed root mean square of successive beat-to-beat interval differences.

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  FIGURE 3. The left panel shows a scatterplot of 24-h values of (ln)HF and heart rate as a function of sex. The right panel illustrates the prediction of heart rate values in both sexes at low, mean, and high (ln)HF values. Higher and lower estimates of (ln)HF were derived from ±1SD from the mean. (ln)HF, natural log-transformed high frequency power.