Table 3.

Correlation coefficients between ${\dot{\text{V}}\text{O}}_2$ at peak exercise and other CPET parameters and the 6-min walk distance.

	$\dot{\text{V}}$O2 (ml/min/kg) at peak exercise
	ρ	p value
$\dot{\text{V}}$E/$\dot{\text{V}}$CO2 at rest	− 0.46	< 0.0001
$\dot{\text{V}}$E/$\dot{\text{V}}$CO2 at peak exercise	− 0.45	< 0.0001
VD/VT at rest	− 0.36	0.002
VD/VT at peak exercise	− 0.53	< 0.0001
Breathing frequency at rest	− 0.35	0.003
Breathing frequency at peak exercise	− 0.33	0.006
6-min walk distance (n = 48)	0.74	< 0.0001

${\dot{V}O}_2$ oxygen uptake, V_T tidal volume, V_E minute ventilation, $\dot{V}$_E/$\dot{V}$_CO2 ventilatory equivalent for carbon dioxide, V_D/V_T dead space to tidal volume ratio.