Cardiac baroreflex sensitivity during repeated handgrip exercise: Comparisons with sit‐stand maneuvers and spontaneous rest

Figures

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  FIGURE 1. Group‐averaged power spectral density (PSD) plots of systolic blood pressure (SBP) and R‐R interval (RRI) during spontaneous rest, repeated handgrip exercise (RHE), and sit‐stand maneuvers (SSM) at 0.10 and 0.05 Hz. Data from 20 participants (10 males and 10 females) are included in theanalysis.

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  FIGURE 2. Power spectral densities of systolic blood pressure (SBP) and R‐R interval (RRI) compared among spontaneous rest, repeated handgrip exercise (RHE), and sit‐stand maneuvers (SSM) by sex. Y‐axes are log‐scaled. Point estimates are used for RHE and SSM (0.10 and 0.05 Hz for low and very low frequencies), while frequency bands are used for spontaneous rest (0.05–0.15 Hz and 0.02–0.07 Hz for low and very low frequencies). Two‐way mixed analysis of variance (ANOVA) compared the three conditions in 10 males and 10 females, with the Bonferroni correction for post‐hoc pairwise comparisons. Reported p‐values include main effects of condition (C), sex (S), and their interaction (C*S). Significant p‐values from post‐hoc tests are shown in the figure.

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  FIGURE 3. Group‐averaged waveforms of transfer function coherence, gain, and phase of the cardiac baroreflex sensitivity (BRSTFA) during spontaneous rest, repeated handgrip exercise (RHE), and sit‐stand maneuvers (SSM) performed at 0.10 and 0.05 Hz. Data from 20 participants (10 males and 10 females) are included.

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  FIGURE 4. Transfer function coherence, gain, and phase of the cardiac baroreflex sensitivity (BRSTFA) compared among spontaneous rest, repeated handgrip exercise (RHE), and sit‐stand maneuvers (SSM) conditions by sex. Point estimates are used for RHE and SSM (0.10 Hz and 0.05 Hz for low and very low frequencies), while frequency bands are used for spontaneous rest (0.05–0.15 Hz and 0.02–0.07 Hz for low and very low frequencies). Two‐way mixed analysis of variance (ANOVA) compared the three conditions in 10 males and 10 females, with the Bonferroni correction for post‐hoc pairwise comparisons. Reported p‐values include main effects of condition (C), sex (S), and their interaction (C*S). Significant p‐values from post‐hoc tests are shown in the figure.

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  FIGURE 5. Correlation between individual changes in heart rate and cardiac baroreflex sensitivity calculated by transfer function analysis in low frequency (i.e., LF BRSTFA gain). Individual changes were calculated by subtracting the RHE or SSM values from the resting values. Point estimate (0.10 Hz) is used for RHE and SSM, while frequency band (0.05–0.15 Hz) is used for spontaneous rest. Correlation coefficients and p‐values were calculated by the Pearson product–moment correlation analysis in 20 participants (10 males and 10 females). RHE: Repeated handgrip exercise, SSM: Sit‐stand maneuvers.

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  FIGURE 6. Hypothetical diagram illustrating the baroreflex curve shifts during repeated handgrip exercise and sit‐stand maneuvers compared to resting spontaneous condition.