TRANSCUTANEOUS P(CO2)-MONITORING FOR THE EVALUATION OF THE ANAEROBIC THRESHOLD - COMPARISON TO LACTATE AND VENTILATORY THRESHOLDS

The monitoring of transcutaneous p(CO2) (p(CO2(tc))) is an alternative to the invasive determination of the anaerobic threshold by analysis of arterial lactate concentration or to the uncomfortable determinatio n of the ventilatory threshold. We compared the threshold determinatio n by p(CO2(tc))-monitoring to the 4 mmol/l lactate threshold and to th e ventilatory threshold (point where the ventilatory equivalent of oxy gen started to increase continuously) in 15 athletes during cycle exer cise. The first distinct deflection point in the p(CO2(tc)) time cours e after the start of exercise was chosen to indicate the anaerobic thr eshold. The mean threshold determined by p(CO2(tc)) occurred at the sa me workload as the ventilatory threshold but at a lower workload than the lactate threshold. In spite of the good correspondence in the resp ective means there was a wide range of individual differences between the p(CO2(tc)) derived thresholds and both reference thresholds. Thus, looking at an individual, the continuous monitoring of the p(CO2(tc)) does not provide reliable data on the occurrence of the transition fr om aerobic to anaerobic metabolism.