End-tidal pressure of CO2 and exercise performance in healthy subjects.
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.
Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia, Università degli Studi di Milano, Via Parea 4, Milan, Italy. Maurizio.bussotti@CCFM.it
Maurizio
M
Bussotti
Damiano
D
Magrì
Emanuele
E
Previtali
Stefania
S
Farina
Anna
A
Torri
Marco
M
Matturri
Piergiuseppe
P
Agostoni
D000328:Adult; D015308:Anaerobic Threshold; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism*; D015444:Exercise; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010313:Partial Pressure; D012123:Pulmonary Ventilation; D012016:Reference Values; D015656:Respiratory Mechanics; D013990:Tidal Volume
D002245:Carbon Dioxide