[Spiroergometrical criteria in the non-invasive evaluation of work-induced variation in lactic acid levels and acid-base equilibrium during unsteady-state exercise (author's transl)].
During an incremental exercise test the spiroergometric parameters Respiratory Quotient (RQ), Ventilatory Equivalent for oxygen (AEO2 = VE/VO2) and Ventilatory Equivalent for carbondioxide (AECO2 = VE/VCO2) initially decrease. These values then increase continuously at various work load levels until exhaustion. Experiments on 40 healthy untrained men between 20 and 40 years of age using upright bicycle ergometry and computer assisted on-line ergospirometry in which the work load was increased each minute by app. 16.3 watts show that the following 3 performance levels can be used to sufficiently describe the incremental exercise test: 1. Minimum AECO2 (77.9 +/- 22.3 watts approximately 1183 +/- 320.1 ml VO2 approximately 45.1 +/- 9.62% VO2 max), 2. Minimum AECO2 (148.5 +/- 32.7 watts approximately 1883 +/- 388.9 ml VO2 approximately 71.8 +/- 11.43% VO2 max), 3. Maximal power output (220.1 +/- 30.6 watts approximately 2638 +/- 442.3 ml VO2) (mean +/- SD). In addition simultaneous determinations of lactic acid levels and acid base equilibrium from arterialized capillary blood sampled at one minute intervals were carried out on a further 15 persons. It is shown that VO2 at the rise of AEO2 from its minimum is closely correlated with VO2 at the first significant increase of lactic acid levels (r = 0.942). There is less correlation between VO2 at the rise of AECO2 from its minimum and VO2 at the begin of the decompensation of the work induced metabolic acidosis (r = 0.854). The results indicate that through the use of spiroergometric parameters it is possible to obtain further information on the peripheral and cardiopulmonary adaptability of the organism under low submaximal work load conditions avoiding the necessity of invasive measurements.