General ventilatory and pulmonary gas exchange responses to submaximal and maximal exercise in endurance trained athletes, asthmatics and obese when compared to normative values

VariableElite endurance trained athleteAsthmaticObese
MaleFemaleBMI 30–40 kg·m−2BMI>40 kg·m−2
Submaximal exercise
V′E/V′CO2 nadirN/AN/AN/A
V′E/V′CO2 y-interceptN/AN/AN/A
V′E-to-V′CO2 slopeN/A
Maximal exercise
V′E/V′CO2 peak↔ or ↓
PaCO2↔ or ↑

V′E/V′CO2: minute ventilation relative to carbon dioxide production; VD/VT: total physiologic dead space as a proportion of tidal volume; PaCO2: arterial partial pressure of CO2; N/A: not available. The arrows represent the direction of change compared to age and height matched normative values [6, 20, 33–36]. ↔: no difference; ↓: decrease; ↑: increase.