[Semi-supine cardiopulmonary stress test in middle-aged probands with healthy hearts].

Normal values for cardiopulmonary bicycle exercise testing in semisupine position using a ramping protocol in a middle-aged group of untrained men and women are presented. We exercised 23 men and 16 women aged from 33 to 66 years without evidence of cardiopulmonary or cardiovascular disease and normal findings during complete heart catheterization. Clinical findings, x-ray, resting and exercise ECG, and laboratory findings were normal. Exercise testing was performed using a ramping protocol with a work rate increase of 20 watts/min. Respiratory gas analysis (breath-to-breath method) was performed and oxygen uptake (VO2), carbon-dioxide production (VCO2), and minute ventilation (VE) were determined at maximal work load and at the ventilatory anaerobic threshold. Work rate increase and heart rate were continuously monitored. From these data oxygen pulse, the respiratory quotient (RQ), and the ventilatory equivalents VE/VO2 and VE/VCO2 were derived. Furthermore, the VO2 to work rate ratio, and the VO2 to heart rate ratio were analyzed. Maximal VO2 was within the 95% confidence interval of predicted VO2max. The anaerobic threshold (V-slope method) was 60% of VO2 max at the RQ of 0.81 for men and 66% of VO2max at the RQ of 0.84 for women. The O2 pulse was 100% of the age predicted value. The VO2 to work rate ratio was 10.7 +/- 1.4 for men and 9.7 +/- 1.2 ml/watts/min for women (p < 0.05). The slope of heart rate to VO2 from rest to peak exercise as a measure of chronotropic competence was nonlinear in 59% of the subjects.(ABSTRACT TRUNCATED AT 250 WORDS)