Relationships of femoral venous [K+], [H+], $$P_{o_2 } $$ , osmolality, and [orthophosphate] with heart rate, ventilation, and leg blood flow during bicycle exercise in athletes and non-athletes, osmolality, and [orthophosphate] with heart rate, ventilation, and leg blood flow during bicycle exercise in athletes and non-athletes

The relationships of femoral venous [K⁺], [H⁺], osmolality (OSM),\(P_{o_2 } \), and [inorganic phosphate] ([Pi]) with heart rate (HR), ventilation (\(\dot V_E \)), and calculated leg blood flow (Q) were investigated during bicycle exercise in endurance trained (TR) and untrained (UT) test subjects. At a given\(\dot V_{o_2 } \) the increases of [K⁺], [H⁺], OSM, [Pi] and the decrease of\(P_{o_2 } \) were significantly lower in TR than in UT. In the same proportion the increases ofHR,\(\dot V_E \), andQ were diminished. Thus in TR and UT identical and highly significantly correlated regression lines of [K⁺], [H⁺], OSM, [Pi], and\(P_{o_2 } \) withHR,\(\dot V_E \), andQ were obtained. These constituents changed in the same proportion as the relative\(\dot V_{o_2 } \) in TR and UT. No relationships with [Na⁺], [Ca⁺⁺], and [Mg⁺⁺] were found. By means of a multiple regression analysis the partial influence of K⁺, H⁺, OSM,\(\dot V_{o_2 } \), and Pi upon the total change ofHR,_E, andQ was estimated, to compare with data from infusion experiments. The findings were discussed in view of the hypothesis that these candidates may provide a possible linkage between metabolic events, circulatory, and ventilatory adjustments during work.