Skip to main content
. Author manuscript; available in PMC: 2015 Jan 1.
Published in final edited form as: Addict Behav. 2013 Sep 13;39(1):10.1016/j.addbeh.2013.09.008. doi: 10.1016/j.addbeh.2013.09.008

Table 2.

Sleep quality, sleepiness, and hangover variables by condition

Beer with Caffeine Beer Alone Effect
size
M (SD) or % M (SD) or % D or h
Minutes to fall asleep 36.5 (67.7) 23.2 (29.4) .28
Minutes asleep 390.7 (73.8) 404.7 (62.5) .21
Average sleep quality a 4.45 (0.41) 4.16 (0.49) .64*
Stanford Sleepiness Scale b 2.52 (1.37) 2.78 (0.90) .23
Acute Hangover Scale score 1.34 (0.84) 1.45 (0.89) .13
Hangover incidence (% yes) 60.7 69.4 .19

Note: N = 28 for beer with caffeine, n = 36 for beer without caffeine condition.

a

Higher score means better perceived sleep quality and morning alertness

b

Mean of ratings at 8:00, 8:30, and 9:00 a.m.; higher scores are more sleepy

*

p < .02.