Table 1.

Sleep parameters during the first and second night of the 4h and 8h-sleep conditions

	4h-sleep	8h-sleep	P
			Condition	Night	Night × Condition
TST (min)
Night I	236 ± 2	465 ± 4	< 0.001	0.294	0.923
Night II	238 ± 1	467 ± 3
WASO (min)
Night I	2 ± 1	18 ± 4	0.002	0.127	0.120
Night II	2 ± 1	9 ± 3
WASO (%)
Night I	1 ± 0	4 ± 1	0.012	0.149	0.143
Night II	1 ± 0	2 ± 1
S1 (min)
Night I	18 ± 2	52 ± 10	0.002	0.051	0.136
Night II	16 ± 1	37 ± 8*
S1 (%)
Night I	7 ± 1	11 ± 2	0.061	0.150	0.127
Night II	7 ± 1	8 ± 2*
S2 (min)
Night I	124 ± 7	255 ± 9	< 0.001	0.097	0.382
Night II	111 ± 7*	254 ± 8
S2 (%)
Night I	52 ± 3	55 ± 2	0.054	< 0.001	0.135
Night II	47 ± 3*	54 ± 2
SWS (min)
Night I	47 ± 7	49 ± 6	0.838	0.001	0.067
Night II	69 ± 7***	61 ± 6**
SWS (%)
Night I	21 ± 3	10 ± 1	< 0.001	0.002	0.018
Night II	29 ± 3**	13 ± 1**
REM (min)
Night I	43 ± 6	87 ± 11	< 0.001	0.146	0.029
Night II	38 ± 5	101 ± 8
REM (%)
Night I	18 ± 2	19 ± 2	0.186	0.626	0.045
Night II	16 ± 2	22 ± 2
MT (min)
Night I	2 ± 0	4 ± 1	< 0.001	0.130	0.223
Night II	3 ± 0	5 ± 1
MT (%)
Night I	1 ± 0	1 ± 0	0.244	0.237	0.567
Night II	2 ± 1	1 ± 0

Data are mean ± SEM. TST, total time spent asleep; WASO, wake time after sleep onset; S1, sleep stage 1; S2, sleep stage 2; SWS, slow wave sleep; MT, movement time during TST. P-values are derived from ANOVA including the factors “Condition” for 4h-hour vs. 8h-sleep condition and Night for comparison of night 1 vs. night 2.

^*P < 0.05;

^**P < 0.01;

^***P < 0.001 for Student t-test comparing night 1 vs. night 2 within conditions.