title: In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial.
abstract: Prolonged wakefulness greatly decreases nocturnal driving performance. The development of in-car countermeasures is a future challenge to prevent sleep-related accidents. The aim of this study is to determine whether continuous exposure to monochromatic light in the short wavelengths (blue light), placed on the dashboard, improves night-time driving performance. In this randomized, double-blind, placebo-controlled, cross-over study, 48 healthy male participants (aged 20-50 years) drove 400 km (250 miles) on motorway during night-time. They randomly and consecutively received either continuous blue light exposure (GOLite, Philips, 468 nm) during driving or 2*200 mg of caffeine or placebo of caffeine before and during the break. Treatments were separated by at least 1 week. The outcomes were number of inappropriate line crossings (ILC) and mean standard deviation of the lateral position (SDLP). Eight participants (17%) complained about dazzle during blue light exposure and were removed from the analysis. Results from the 40 remaining participants (mean age ± SD: 32.9±11.1) showed that countermeasures reduced the number of inappropriate line crossings (ILC) (F(2,91.11) = 6.64; p<0.05). Indeed, ILC were lower with coffee (12.51 [95% CI, 5.86 to 19.66], p = 0.001) and blue light (14.58 [CI, 8.75 to 22.58], p = 0.003) than with placebo (26.42 [CI, 19.90 to 33.71]). Similar results were found for SDLP. Treatments did not modify the quality, quantity and timing of 3 subsequent nocturnal sleep episodes. Despite a lesser tolerance, a non-inferior efficacy of continuous nocturnal blue light exposure compared with caffeine suggests that this in-car countermeasure, used occasionally, could be used to fight nocturnal sleepiness at the wheel in blue light-tolerant drivers, whatever their age. More studies are needed to determine the reproducibility of data and to verify if it can be generalized to women.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01070004.
authors.affiliation: University of Bordeaux, Sommeil, Attention et Neuropsychiatrie, USR 3413, Bordeaux, France. jack.taillard@gmail.com
authors.forename: Jacques
authors.initials: J
authors.lastname: Taillard
authors.forename: Aurore
authors.initials: A
authors.lastname: Capelli
authors.forename: Patricia
authors.initials: P
authors.lastname: Sagaspe
authors.forename: Anna
authors.initials: A
authors.lastname: Anund
authors.forename: Torbjorn
authors.initials: T
authors.lastname: Akerstedt
authors.forename: Pierre
authors.initials: P
authors.lastname: Philip
mesh_terms: D000328:Adult; D001334:Automobile Driving; D002110:Caffeine / Q000494:pharmacology; D003069:Coffee / Q000737:chemistry; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005221:Fatigue / Q000517:prevention & control*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D010919:Placebos; D011597:Psychomotor Performance / Q000187:drug effects / Q000528:radiation effects; D015203:Reproducibility of Results; D012892:Sleep Deprivation; D012894:Sleep Stages / Q000528:radiation effects; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*
chemical_list: D003069:Coffee; D010919:Placebos; D002110:Caffeine