Suppression of sleepiness in drivers: combination of caffeine with a short nap.
Previous research has shown that caffeine and a < 15-min nap effectively and separately reduce sleepiness in drivers for 1 hr. In the present study, we examined in 12 sleepy individuals the treatments combined, taken during a 30-min break, prior to a longer (2 hr) continuous monotonous afternoon drive in a car simulator. Nonnap comparisons were 200 mg caffeine only and placebo. For placebo, driving incidents, subjective and electroencephalographic measures of sleepiness all reflected a mid-afternoon peak. This peak was significantly reduced by caffeine and eliminated by the combined treatment, which reduced incidents to 9% of placebo levels versus 34% of placebo levels for caffeine alone. Naps comprising "nonsleep dozing" were still effective.
Reyner
L A
LA
Sleep Research Laboratory, Loughborough University, Leicestershire, UK. l.a.reyner@lboro.ac.uk
Horne
J A
JA
D000328:Adult; D001334:Automobile Driving; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D012890:Sleep / Q000187:drug effects / Q000502:physiology*; D012894:Sleep Stages / Q000187:drug effects*
D000697:Central Nervous System Stimulants; D002110:Caffeine