Plasma volume, osmolality, vasopressin, and renin activity during graded exercise in man.

摘要: Plasma volume (PV), renin activity (PRA), and osmotic (Osm), sodium (Na+), arginine vasopressin (AVP) concentrations were measured in venous blood samples taken before after three levels of cycle ergometer exercise (100, 175, 225 W) 15 young male volunteers. solute changed significantly (P less than 0.05, denoted by *) with work intensity. The % delta PV was -3.7%* at 100 W, -8.8%* 175 -12.4%* W. Na+ concentration, Osm, AVP increase curvilinear graded significant only when intensity exceeded 40% VO2max. PRA linear all levels. correlated Osm (r = 0.99*) 0.89*) but had low correlations 0.22, NS) 0.12, NS). However, 0.86*) 0.83*), whereas 0.33, NS), 0.29, 0.43, data support the hypothesis that a) exercise, release is a primary factor for fluid electrolyte regulation as it highly plasma hyperosmolality produced net hypotonic efflux; b) an greater VO2max required to change osmolality and, thus, stimulate release; c) stimulation renin-angiotensin system more general stress response, which responds increasing sympathetic nervous activity.