TABLE 3.

Overview of sleep fragmentation outcomes in each level of both independent variables (i.e., activity and PO₂).

	pNAMB	NBR	HAMB	HBR
	M ± SD (n = 8)	M ± SD (n = 8)	M ± SD (n = 10)	M ± SD (n = 12)
Non-imputed data
ArI (# of events/h of TST)	11.2 ± 3.8	10.5 ± 4.2	32.1 ± 16.6	31.4 ± 19.1
Arousals (# of events)	67 ± 31	72 ± 33	210 ± 110	190 ± 103
RERA (# of events)	38 ± 24	49 ± 33	165 ± 108	160 ± 92
MRA (# of events)	9 ± 6	11 ± 5	11 ± 7	9 ± 6
SAR (# of events)	21 ± 13	13 ± 7	34 ± 13	21 ± 13
	pNAMB	NBR	HAMB	HBR
	M ± SD (n = 12)	M ± SD (n = 12)	M ± SD (n = 12)	M ± SD (n = 12)
Imputed data
ArI (# of events/h of TST) +	11.3 ± 3.3	10.7 ± 3.4	32.2 ± 15.0	31.4 ± 19.1
Arousals (# of events) +	66 ± 26	77 ± 28	203 ± 103	190 ± 103
RERA (# of events) +	39 ± 20	49 ± 27	163 ± 98	160 ± 92
MRA (# of events)	11 ± 6	12 ± 5	11 ± 7	9 ± 6
SAR (# of events) + ^	23 ± 11	14 ± 6	35 ± 12	21 ± 13

Mean (M) and standard deviation (SD) are depicted for both the data set with- and the data set without imputed data. Statistical analysis was performed on the imputed dataset only.

*Indicates a significant interaction effect between PO₂ and activity, +indicates a significant main effect of PO₂, ^indicates a significant main effect of activity; PO₂, partial pressure of oxygen; pNAMB, pseudo normobaric normoxic ambulatory; NBR, normobaric normoxic bed rest; HAMB, normobaric hypoxic ambulatory; HBR, normobaric hypoxic bed rest; ArI, arousal index; Arousals, total number of arousals; RERA, respiratory-related arousals; MRA, movement-related arousals; SAR, spontaneous arousals.