Table 4.

Respiratory Responses to Arousal from Sleep

Respiratory Variable	Group	Breath Post Tone
		1	2	3	4	5	6
Change in VI (Lmin−1)	Young Males	0.02 ± 0.2	2.3 ± 0.4	2.2 ± 0.4	1.5 ± 0.3	1.0 ± 0.3	0.8 ± 0.3
	Young Females	0.7 ± 0.5	2.5 ± 0.3	1.5 ± 0.3	0.8 ± 0.2	0.4 ± 0.2	0.3 ± 0.2
	Older Males	−0.8 ± 0.5	1.8 ± 0.7	1.4 ± 0.5	1.3 ± 0.5	0.9 ± 0.3	0.7 ± 0.3
	Older Females	0.5 ± 0.4	2.0 ± 0.5	1.4 ± 0.2	0.8 ± 0.2	0.4 ± 0.2	0.3 ± 0.2
Change in VT (L)	Young Males	−0.03 ± 0.02	0.1 ± 0.03	0.1 ± 0.03	0.1 ± 0.04	0.07 ± 0.02	0.06 ± 0.02
	Young Females	0.03 ± 0.03	0.1 ± 0.02	0.07 ± 0.02	0.04 ± 0.01	0.02 ± 0.02	0.01 ± 0.01
	Older Males	−0.05 ± 0.07	0.09 ± 0.05	0.08 ± 0.03	0.07 ± 0.03	0.05 ± 0.02	0.04 ± 0.03
	Older Females	0.03 ± 0.05	0.2 ± 0.09	0.1 ± 0.03	0.09 ± 0.03	0.06 ± 0.03	0.05 ± 0.03
Change in RL * (cm H2O.l−1s−1)	Young Males not on CPAP (n=14)	−2.93 ± 1.05	−3.61 ± 0.81	−4.4 ± 1.42	−3.91 ± 1.35	−3.32 ± 0.99	−3.63 ± 0.81
	Older Males on CPAP (n=14)	−0.77 ± 0.57	−1.51 ± 0.89	−1.85 ± 1.03	−1.60 ± 0.90	−1.81 ± 0.93	−1.48 ± 0.80

Values are mean ± SEM. V_I, minute ventilation; V_T, tidal volume; R_L, inspiratory pulmonary resistance.