Fig. 3

Effect of deep breathing (DB) + hand grip (DB + HG) on heart rate variability (HRV) during recovery period 2 in women. A Representative time-varying spectrum of HRV during baseline period, DB + HG, and recovery period 2 from one woman. Note that the power spectral density at low frequency (LF, 0.04–0.08 Hz) and high frequency (HF, 0.08–0.45 Hz) component of HRV, were increased and decreased, respectively, during recovery period 2 compared to the baseline. B Summary data of LF to HF ratio during baseline, DB + HG and during recovery period 2. Note that LF/HF ratio was significantly reduced in recovery period 2 compared to the baseline. C Summary data of LF and HF during baseline, DB + HG, and during recovery period 2. D, E Interindividual response of LF and HF of HRV in men, respectively. Data analyzed via one-way ANOVA, followed by Holm-Sidak post hoc. *p < 0.05; ***p < 0.001