Source avec lien : Journal of Safety Research, 74, septembre 2020. 10.1016/j.jsr.2020.06.003
Le travail de nuit nécessite une inversion du cycle naturel diurne de repos de l’activité humaine et est associé à une baisse de la vigilance et de certaines mesures de performance, à une réduction de la sécurité, à des effets néfastes sur la santé et à une perturbation chronique du cycle de la mélatonine qui a été associée à un risque accru de plusieurs maladies importantes. Des études antérieures montrent que l’exposition à la lumière rouge la nuit peut favoriser la vigilance et améliorer les performances sans avoir d’effets négatifs sur la sécrétion de mélatonine. Cette étude de terrain en cours, croisée et mixte (intra- et inter-sujets), teste l’efficacité et l’acceptation de la lumière rouge délivrée aux travailleurs de jour et de nuit utilisant des lunettes lumineuses personnelles pendant qu’ils sont au travail.
Introduction: Night work requires inversion of the natural, diurnal human activity-rest cycle and is associated with decreased alertness and some measures of performance, reduced safety, adverse health effects, and chronic disruption of the melatonin cycle that has been associated with increased risk for several major diseases. Previous studies show that red light exposures at night can promote alertness and improve performance while not negatively affecting melatonin secretion. Method: This ongoing crossover, mixed (within- and between-subjects) design field study is testing the efficacy and acceptance of red light delivered to day-shift and night-shift workers using personal light glasses while they are at work. Each participant experienced three lighting interventions at the eyes: red light (50 lx, 630 nm, the treatment intervention), blue light (50 lx, 460 nm, the positive control intervention), and dim white light (10 lx, 3,000 K, the placebo control). During the interventions, participants underwent visual performance testing, submitted salivary melatonin and cortisol samples, and provided subjective reports of sleepiness, sleep disturbance, and general health over the 20-week protocol. Due to the ongoing nature of the study, only the performance and subjective reports are presented here. Results: Preliminary results indicate that response times were improved by the red and blue interventions, but not accuracy and hit rates. Blue light was associated with improvements to self-reported sleep disturbances compared to dim light. Conclusions: These field results partially support our laboratory results that showed a positive effect of red light for promoting alertness and certain performance outcomes during the day and at night. Practical Applications: Red light may be used to improve response times in shift workers. Continued research will elucidate the lighting interventions’ effects on melatonin and objective sleep measures (actigraphy).