Time course of cardiovascular responses to acute sustained handgrip exercise in young physically active men

We aimed to assess currently unexplained effects of isometric exercise on central hemodynamic, arterial, and cardiac cycle parameters. Twenty-three young physically active males performed 5-min forearm sustained exercise at 20% of maximum voluntary contraction. The pulse wave analysis (SphygmoCor) was conducted at baseline (BL) and at 1, 5, 10, 15, and 20 min of post-load recovery. The General Linear Model repeated measures analysis with post hoc test was used to compare the BL values, 1-min, and 15-min recovery states. Exercise immediately elevated central and peripheral systolic blood pressure (BP), augmentation index, left ventricular contractility, and its relative relaxation time. These prompt reactions were followed by a hypotensive response and positive lusitropic effect with shortening relaxation in 15 min after the contraction ceased. The diastolic BP decrement was inversely correlated with the amount of body lean mass and body muscle but not fat mass measured by the bioelectrical impedance method. It is hypothesized that (1) the body lean mass-dependent BP-lowering effect of exercise is due to the arterial distending influence of metabolites accumulated in the muscle during exercise-induced occlusion and then washed out into general circulation, and (2) muscle arteries are more sensitive to these effects than vessels of fat tissue.