Prediction of stroke volume from oxygen pulse measurements in untrained and trained men

This study examined the relationship of oxygen pulse (O2 pulse) to stroke volume (SV) and arterio-venous oxygen difference [(a-v)O2 diff] during submaximal cycle exercise in untrained (UG) and trained (TG) males. Fourteen volunteers in each group completed an incremental VO2 max test and a submaximal test at 60% VO2 max to determine cardiac output (Q) via CO2 rebreathing. VO2, Q, and heart rate (HR) were used to calculate SV and (a-v)O2 diff. There were no significant differences (p > .05) between the two groups for O2 pulse, SV, and (a-v)O2 diff during submaximal exercise. Stroke volume index (SVI) was significantly higher (p < .05) in the TG. O2 pulse was significantly related to SV and SVI (p < .05) but not to (a-v)O2 diff in both groups. Regression equations for predicting SV from O2 pulse for UG and TG were Y = 6.81X + 26.7, SE = 21.4, r = 0.84, and Y = 10.33X - 32.3, SE = 14.2, r = 0.71, respectively. These results suggest that O2 pulse can be used to predict SV during submaximal cycle exercise in untrained and trained men.