Figure 4.

The relationships between the PaO₂-slope and the PaO₂ at peak exercise during cardiopulmonary exercise testing. 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). The horizontal lines represent the standard deviation. The dots between the horizontal lines represent the mean. PaO₂, arterial oxygen tension.