Usefulness of the Oxygen Uptake Efficiency Slope in the Evaluation of Cardiorespiratory Fitness of the Stroke Patients

ABSTRACT

OBJECTIVE: To investigate the usefulness of the oxygen uptake efficiency slope (OUES) in the evaluation of cardiorespiratory fitness of the stroke patients. METHOD: 25 stroke patients who could walk independently were included in this syudy. The symptom-limited graded treadmill test was performed to assess cardiovascular fitness. During the test, minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER) and anaerobic threshold (AT) were measured through respiratory gas analysis. A linear relationship was established between the oxygen consumption and the logarithmic transformation of minute ventilation. From this linear relationship, we obtained a slope that represented the OUES. OUES values were obtained from data corresponding to 75% (OUES75), 90% (OUES90) and 100% (OUES100) of the exercise duration. RESULTS: The differences among OUES75, OUES90 and OUES100 groups were not statistically significant and these three groups were highly correlated to each other. Maximal oxygen consumption (VO2max) was positively correlated with OUES75 (r=0.723), OUES90 (r=0.762), OUES100 (r=0.809) and AT (r=0.696), respectively (p<0.01). CONCLUSION: OUES is considered to be the valuable submaximal index to evaluate the cardiorespiratory fitness of stroke patients who can not reach maximal exercise.