Table 2. Means, Standard Errors of the Mean (SEM), and P-values for Pairwise Comparisons between Conditions Regarding Time Spent in Different Sleep Stages (Relative to Total Sleep Time; N=15 Men and 15 Women), EEG Power (Percent of Total Power between 0.5 and 50 Hz; N=15 Men and 13 Women) in the Slow Oscillation (0.5–1 Hz) and Sleep Spindle (12–15 Hz) Band during the First and the Second 90 min of NonREM Sleep, Reaction Speed (1/Reaction Time; N=16 Men and 12 Women), and Sleepiness (According to the Stanford Sleepiness Scale; N=16 Men and 16 Women).

Measure	Insulin		Placebo		P
	Mean	SEM	Mean	SEM
Sleep stage
Wake (%)	1.96	(0.6)	1.72	(0.53)	0.76
S1 (%)	7.76	(0.91)	7.54	(0.93)	0.76
S2 (%)	54.09	(1.37)	54.50	(1.46)	0.74
S3 (%)	8.01	(0.72)	8.08	(0.76)	0.87
S4 (%)	7.57	(1.02)	7.51	(1.08)	0.93
REM (%)	19.68	(0.89)	19.58	(0.92)	0.93
Total sleep (min)	460.3	(3.33)	458.73	(4.93)	0.71
Slow oscillation band (0.5–1 Hz)
C3 1st NonREM	33.8	(1.05)	33.24	(0.88)	0.57
C4 1st NonREM	33.83	(0.89)	34.46	(0.78)	0.28
C3 2nd NonREM	35.46	(0.95)	37.46	(1.52)	0.23
C4 2nd NonREM	36.12	(1.03)	36.82	(0.95)	0.42
Sleep spindle band (12–15 Hz)
C3 1st NonREM	2.82	(0.25)	2.91	(0.24)	0.64
C4 1st NonREM	2.81	(0.27)	2.77	(0.24)	0.79
C3 2nd NonREM	4.06	(0.37)	4.04	(0.40)	0.95
C4 2nd NonREM	4.03	(0.38)	3.92	(0.40)	0.61
Reaction speed
2205 hours	2.93	(0.06)	3.01	(0.06)	0.06
2240 hours	2.92	(0.06)	2.85	(0.07)	0.07
0805 hours	3.04	(0.07)	2.97	(0.07)	0.17
1915 hours	2.96	(0.07)	2.99	(0.07)	0.56
Sleepiness
2120 hours	2.84	(0.17)	3.00	(0.20)	0.33
2240 hours	3.44	(0.17)	3.50	(0.20)	0.74
0805 hours	2.81	(0.18)	2.97	(0.21)	0.36
1805 hours	2.13	(0.19)	2.47	(0.15)	0.09