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Updated: Jul 4, 2026

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method
Published on: February 2, 2024
End-tidal pressure of CO2 and exercise performance in healthy subjects
Maurizio Bussotti1, Damiano Magrì, Emanuele Previtali
1Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia, Università degli Studi di Milano, Via Parea 4, Milan, Italy. Maurizio.bussotti@CCFM.it
Abstract:
High arterial CO(2) pressure (P(a)CO(2)) measured in athletes during exercise suggests inadequate hyperventilation. End-tidal CO(2) pressure (P (ET)CO(2)) is used to estimate P(a)CO(2.) However, P(ET)CO(2) also depends on exercise intensity (CO(2) production, .VCO2) and ventilation efficiency (being P(ET)CO(2) function of respiratory rate). We evaluated P(ET)CO(2) as a marker, which combines efficiency of ventilation and performance. A total of 45 well-trained volunteers underwent cardiopulmonary tests and were grouped according to P(ET)CO(2) at respiratory compensation (RC): Group 1 (P(ET)CO(2) 35.1-41.5 mmHg), Group 2 (41.6-45.7) and Group 3 (45.8-62.6). At anaerobic threshold, RC and peak exercise, ventilation (.VE) was similar, but in Group 3, a greater tidal volume (Vt) and lower respiratory rate (RR) were observed. Peak exercise workload and .VO2 were lowest in Group 1 and similar between Group 2 and 3. Group 3 subjects also showed high peak .VCO2 suggesting a greater glycolytic metabolism. In conclusion, a high P(ET)CO(2) during exercise is useful in identifying a specific respiratory pattern characterized by high tidal volume and low respiratory rate. This respiratory pattern may belong to subjects with potential high performance.
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