Table 1.

Differences in Sleep Architecture Between Older and Younger Subjects

Sleep Measure	Younger subjects (n=18)	Older subjects (n=13)
Total sleep time	392.3 min ± 11.2	367.8 min ± 11.0
Sleep efficiency	85.7% (median)	85.0% (median)
%NREM 1	13.2% ± 1.1	16.5% ± 1.9
%NREM2	39.5% ± 1.8	46.9% ± 2.7*
%NREM 3 (SWS)	32.3% ± 2.1	16.2% ± 2.8**
%REM	15.1% ± 1.3	20.3% ± 2.3*
AHI4%	0.6/hour (median)	0.9/hour (median)
AHI3%all	4.0/hour (median)	5.4/hour (median)
NREM 1 mean bout length	1.0 min (median)	1.0 min (median)
NREM 2 mean bout length	2.6 min ± 0.2	2.6 min ± 0.2
NREM 3 (SWS) mean bout length	5.9 min ± 0.7	2.0 min ± 0.3**
REM mean bout length	8.8 min ± 1.0	6.5 min ± 0.7

Key: NREM1 = non-REM stage 1, NREM2 = non-REM stage 2, NREM3 = non-REM stage 3, SWS = slow wave sleep.

^*= p < 0.05

^**= p < 0.001.