Table 5.

Body mass index (BMI), inspiratory fraction (IC/TLC), and total lung capacity (TLC)% correlated with the variables significant differences across the three O₂P patterns (N = 45).

	Correlation Coefficients
	BMI	IC/TLC	TLC%
Cardiothoracic ratio	0.641‡	0.395*	−0.497**
EDRV, cm2	0.399†	0.168	−0.216
IC/TLC	0.284¶	—	−0.486†
TLC%	−0.462**	—	—
Diffusing capacity for CO% pred.	0.507†	0.364*	−0.253¶
Maximum expiratory pressure pre, cmH2O	0.434**	0.063	−0.358*
Maximum inspiratory pressure post-pre, cmH2O	0.133	−0.17	0.009
O2Ppeak, mL/beat	0.418**	0.357*	−0.138
O2Ppeak, operable, mL/beat	0.427**	0.348*	−0.149
VT/TI/$\dot{\mathrm{V}}$O2 peak	−0.325*	0.001	0.13
Inspiratory duty cycle peak	−0.399**	0.139	−0.216
Minute ventilation/$\dot{\mathrm{V}}$O2 peak	−0.418**	0.082	0.21
Minute ventilation/$\dot{\mathrm{V}}$ CO2 peak	−0.486†	−0.16	0.339*
Breathing frequency peak, breath/min	−0.119	0.214	−0.075
Rapid shallow breathing index peak, breath/min/L	−0.231	−0.19	−0.054

EDRV: subcostal 4-chamber view end-diastolic right ventricle area, CO: carbon monoxide, pre: before exercise, post-pre: difference between after and before exercise, V_T/T_I/$\dot{\mathrm{V}}$O₂peak: tidal volume and inspiratory time ratio normalized by oxygen uptake at peak exercise, $\dot{\mathrm{V}}$CO₂: CO₂ output. ^* p < 0.05, ^**<0.01, ^†<0.001, ^‡<0.0001, ^¶<0.1.