Figure 5.

The relationships of the ${\text{HCO}}_3^{-}$ levels at peak exercise during cardiopulmonary exercise testin. (i) relationship between PaO₂ and ${\text{HCO}}_3^{-}$, (ii) relationship between PaCO₂ and ${\text{HCO}}_3^{-}$, (iii) relationship between lactate and ${\text{HCO}}_3^{-}$, and (iv) relationship between ${\stackrel{°}{\text{V}}}_{\text{E}}$ and ${\text{HCO}}_3^{-}$. Group A (< 11 mL·min⁻¹·kg⁻¹); group B (11 to < 15 mL·min⁻¹·kg⁻¹); group C (15 to < 21 mL·min⁻¹·kg⁻¹); and group D (≥21 mL·min⁻¹·kg⁻¹). ${\text{HCO}}_3^{-}$, bicarbonate ion; PaCO₂, arterial carbon dioxide tension; PaO₂, arterial oxygen tension; ${\stackrel{°}{\text{V}}}_{\text{E}}$, minute ventilation.