Table 4.

Analysis of contributing factors for the differences in exercise time between both groups

Contributing factors	Simple regression			Multiple regression (backward variable selection P < 0.05)
	Regression coefficient	95% confidence interval	P value	Regression coefficient	95% confidence interval
Submax D-Minute ventilation (L/minute)	−10.970	(−17.033, −4.908)	0.0002
Submax D-Oxygen uptake (mL/minute)	−0.457	(−0.672, −0.241)	<0.0001	−0.251	(−0.465, −0.038)
Submax D-Arterial pH	−0.409	(430.835, 3061.407)	0.013
Submax D-Norepinephrine (ng/mL)	−111.811	(−185.165, −38.457)	0.0006
Submax D-Carbon dioxide production (mL/minute)	1746.121	(−0.573, −0.246)	<0.0001
Submax D-Lactate (mEq/L)	−61.461	(−88.392, −34.530)	<0.0001	−41.255	(−70.117, −12.393)

Abbreviation: D, difference.