During effort an excess of carbon dioxide (CO2excess) is produced and results stechiometrically from the quantity of protons bound in bicarbonate buffering. It has been found that CO2excess correlates with the recruitment of anaerobic glycolysis and lactate accumulation during laboratory simulation of various types of exercise (1,2). In this study ten male young high level indoor football players were recruited. They performed a field shuttle test consisting of 8, 30m running sprints at the maximal speed possible separated by 10 s of recovery. At the end of the test, blood samples were obtained with a finger prick in order to obtain lactate concentration by using a portable lactate analyser. Subjects also wore throughout the test and recovery a portable metabolic system which provided values of oxygen uptake (VO2) and carbon dioxide production (VCO2). CO2excess was measured by the following equation: CO2excess= VCO2-(RERrest•VO2), where RERrest is the respiratory exchange ratio at rest. Correlation between peak blood lactate (Bla-peak) and the amount of CO2excess during recovery was assessed by the non-parametric Spearman correlation. Results showed that there was a significant correlation between Bla-peak and CO2excess (r=0.74, p=0.01). Thus, it was concluded that CO2excess yields good estimate of lactate production during field test in athletes.

1) Crisafulli et al. Am. J. Physiol. (Heart Circ. Physiol.) 2006

2) Crisafulli et al. Int. J. Sports Med. 2006.