Evaluating sleep deprivation and time-of-day influences on crash avoidance maneuvers of young motorcyclists using a dynamic simulator

Introduction: Motorcyclists are particularly at risk of being injured when involved in a road traffic accident. To avoid such crashes, emergency braking and/or swerving maneuvers are frequently performed. The recent development of dynamic motorcycle simulators may allow to study the influences of various disturbance factors such as sleep deprivation (SD) and time-of-day (TOD) in safe conditions. Methods: Twelve young healthy males took part in 8 tests sessions at 06:00 h, 10:00 h, 14:00 h, 18:00 h after a night with or without sleep, in a random order. Participants had to perform an emergency braking and a swerving maneuver, both realized at 20 and 40 kph on a motorcycle dynamic simulator. For each task, the total distance/time necessary to perform the maneuver was recorded. Additional analysis was conducted on reaction and execution distance/time (considered as explanatory variables). Results: Both crash avoidance maneuvers (emergency braking and swerving) were affected by increased speed, resulting in longer time and distance at 40 kph than at 20 kph. Emergency braking was mainly influenced by sleep deprivation, which significantly increased the total distance necessary to stop at 40 kph (+1.57 m; + 20%; p < 0.01). These impaired performances can be linked to an increase in reaction time (+21%; p < 0.01). Considering the swerving maneuver, TOD and SD influences remained limited. TOD only influenced the reaction time/distance measured at 40 kph with poorer performance in the early morning (+30% at 06:00 h vs 18:00 h; p < 0.05). Discussion: Our results confirm that crash avoidance capabilities of young motorcyclists were influenced by the lack of sleep, mainly because of increased reaction times. More complex tasks (swerving maneuver) remained mostly unchanged in this paradigm. Practical Applications: Prevention campaigns should focus on the dangers of motorcycling while sleepy. Motorcycling simulators can be used to sensitize safely with sleep deprivation and time-of-day influences.     

Red light: A novel,non-pharmacological intervention to promote alertness in shift workers

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).     

铁路机车乘务员睡眠状况调研

为进一步了解机车乘务员睡眠状况及影响因素,以更好改善职工睡眠状况、为保证行车安全提供依据。采用阿森斯失眠量表及睡眠呼吸障碍问卷等心理测量法,选取某铁路局集团公司864名机车乘务员开展相关调研。结果表明,机车乘务员睡眠问题较严重,有失眠和可疑失眠的机车乘务员合计占调查人员总数的96.5%;睡眠问题主要表现为睡不好和睡觉中打呼噜,分别占调查中有失眠问题机车乘务员总数的86.7%和65.3%;工作环境和工作压力大导致的睡眠问题是机车乘务员失眠的主要原因,体重指数超标与患阻塞性睡眠呼吸暂停风险的机车乘务员占有失眠问题人员总数比例较高。进而提出加大睡眠健康宣传、降低职工体重指数及患阻塞性睡眠呼吸暂停的风险、改善机车乘务员工作环境、提高职工自我心理调节能力等改善职工睡眠质量的建议。