Detection of exercise-induced lactic acidosis using transcutaneous carbon dioxide.

Transcutaneous PCO2 (PtcCO2) measurements were used to monitor changes in systemic lactate levels during exercise. PtcCO2 increased in all 17 male volunteers, and this increase was significantly correlated with increases in measured plasma lactate concentration. In six volunteers, the PtcCO2 increase was greatest during the last minutes of work, indicating rapid lactic acid elimination from the muscles. In these six subjects, the rate of this increase also correlated significantly with the lactate increase. This technique is potentially of interest for detecting fatigue in athletes and for monitoring lactoacidosis as an indicator of circulatory impairment in shock patients.