Table 3.

Timing responses to induced flow limitation

	Inspiratory Time, s		Expiratory Time, s		Total Time, s		Duty Cycle		Respiratory Rate, breaths/min
	Control	COPD	Control	COPD	Control	COPD	Control	COPD	Control	COPD
Baseline	1.6 ± 0.1	1.5 ± 0.1	2.4 ± 0.2	2.5 ± 0.3	3.9 ± 0.2	4.1 ± 0.3	0.41 ± 0.02	0.40 ± 0.02	16.0 ± 0.9	15.5 ± 0.9
IFL	1.8 ± 0.1*	1.8 ± 0.1*	1.8 ± 0.2*	1.5 ± 0.1*	3.6 ± 0.3	3.3 ± 0.2*	0.51 ± 0.02*	0.55 ± 0.02*†	18.1 ± 1.6	18.9 ± 1.1*

Values are averages ± SE. Timing responses are shown for 12 COPD patients and 12 controls matched by sex, BMI (30.6 ± 1.3 vs. 29.8 ± 2.0 kg/m²), and passive Pcrit (−0.7 vs. −0.7 cmH₂O). IFL, inspiratory flow limitation.

^*P < 0.05, comparison between flow-limited condition and non-flow-limited condition.

^†P < 0.05, comparison between response to flow limitation in patients with COPD and matched controls.