The dynamic adjustment of mean arterial pressure during exercise: A potential tool for discerning cardiovascular health status

Abstract

The regulation of mean arterial pressure (MAP) during exercise has important physiological and clinical implications. Kinetics analysis on numerous physiological variables following the transition from unloaded-to-loaded exercise has revealed important information regarding their control. Surprisingly, the dynamic response of MAP during this transition remains to be quantified. Therefore, ten healthy participants (5/5 M/F, 24±3 years) completed repeated transitions from unloaded to moderate- and heavy-intensity dynamic single-leg knee-extensor exercise to investigate the on-kinetics of MAP. Following the transition to loaded exercise, MAP increased in a first-order dynamic manner, subsequent to a time delay (moderate:23±10; heavy:19±9 s, P>0.05) at a speed (tau, moderate:59±30; heavy:66±19 s, P>0.05) which did not differ between intensities, but the MAP amplitude was doubled during heavy-intensity exercise (moderate:12±5; heavy:24±8 mmHg, p<0.001). The reproducibility (coefficient of variation (CV)) during heavy-intensity for unloaded baseline, amplitude, and mean response time, when assessed as individual transitions were 7±1, 18±2, and 25±4%, respectively. Averaging two transitions improved the CVs to 4±1, 8±2, and 13±3%, respectively. Preliminary findings supporting the clinical relevance of evaluating MAP kinetics in middle-aged hypertensive (n=5) and, age-matched, normotensive (n=5) participants revealed an exaggerated MAP response in both older groups (P<0.05), but the MAP response was slowed only for the patients with hypertension (P<0.05). It is concluded that kinetics modeling of MAP is practical for heavy-intensity knee-extensor exercise and may provide insight into cardiovascular health and the effect of aging.