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

Summary

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.