Immediate post-isometric exercise cardiovascular responses are associated with training-induced resting systolic blood pressure reductions.

PURPOSE: The purpose of this study was twofold: (1) to investigate the effect of 4 weeks of bilateral-leg isometric exercise training on the immediate isometric post-exercise cardiovascular responses, and (2) to ascertain whether any changes in immediate post-exercise cardiovascular responses may be associated with training-induced adaptations in resting blood pressure.
METHODS: Thirteen normotensive males completed both isometric exercise training (IET) and control conditions, which were separated by 6 weeks. Participants performed a total of twelve training sessions; 4 × 2-min bilateral-leg isometric exercise bouts separated by 3-min rest periods, 3 days week(-1).
RESULTS: Four weeks of bilateral-leg IET resulted in a reduction in resting SBP (120 ± 12-115 ± 12 mmHg, p = 0.01). The intercept of the 5-min post-exercise systolic blood pressure slope was lower (p = 0.015) following the 4-week training intervention. Individual changes in immediate post-exercise response SBP were also significantly correlated with reductions in resting SBP following 4 weeks of training. There were significant differences in the slopes of the first vs. final post-exercise BRS response (p = 0.009), and the intercepts of the HRR slopes (p = 0.04) recorded during the 5-min post-exercise periods.
CONCLUSIONS: Four weeks of IET altered immediate cardiovascular responses to an individual IET session. Altered immediate responses were also associated with training-induced reductions in resting SBP. To our knowledge, this is the first evidence suggesting that very short-term (immediate) cardiovascular responses may be important in defining chronic reductions in resting blood pressure following a period of IET.