Slow‐release caffeine as a countermeasure to driver sleepiness induced by partial sleep deprivation

Abstract

The effect of partial sleep deprivation (PSD) on driving abilities, as measured with a driving simulator, and the value of slow‐release caffeine as a countermeasure to the expected performance decrements, were studied. Twelve subjects, between 20 and 25 years of age, underwent four experimental conditions, 4.5 or 7.5 h time in bed (TIB) with 300 mg slow‐release caffeine or placebo, according to a Latin square design. Driving performance was measured twice by a 45‐min driving task on a simulator. Subjective sleepiness/alertness and mood were assessed four times, by means of the Stanford Sleepiness Scale (SSS) and Profile of Mood States (POMS). After 4.5 h as compared with 7.5 h TIB lane drifting and speed deviation were higher, but only the effect on the first variable reached significance. In the placebo condition at 13.00 h, accident liability increased after PSD. Subjective sleepiness was higher in the 4.5 h TIB group. Caffeine intake gave rise to a decrease in lane drifting and after PSD it led to a smaller speed deviation and accident liability. The findings suggest that a lack of sleep can lead to a significant driving performance impairment, with drivers having problems to maintain an appropriate road position and a posted speed and more drivers getting involved in an accident. Secondly, the results indicate that caffeine – more specifically slow‐release caffeine – can serve as a valuable countermeasure to these performance decrements, in the absence of any important side‐effects, especially when its application is of an acute nature and when there is no opportunity to take a nap.

Heat Loss, Sleepiness, and Impaired Performance after Diazepam Administration in Humans

“…That increased physiological sleepiness can cause impaired psychomotor performance has been shown in human extended-wakefulness studies (De Gennaro et al, 2001;Nakano et al, 2000;Thomas et al, 2000), shift-work model (Porcu et al, 1998), a clinicopathologic survey for disorders characterized by excessive daytime sleepiness (Cohen-Zion et al, 2001;Hood and Bruck, 1996;Kinnari et al, 2000;Schulz et al, 1997), and a clinicopharmacological survey of alertness-modifying drugs such as caffeine, modafinil, and melatonin (De Valck and Cluydts, 2001;Nave et al, 2002;Wesensten et al, 2002). Although it remains unclear whether impaired psychomotor performance after DZP administration could also be caused by increased sleepiness, the magnitude of heat loss induced by Bz agonist may be a potent indicator to predict sedative effects on brain function.…”

“…Recent studies have shown that the sleep-producing mechanism in humans is preceded by increased heat loss (Campbell and Broughton, 1994;Gilbert et al, 1999;Krauchi et al, 1999Krauchi et al, , 1997 and that various sleep-producing manipulations act, at least in part, by enhancing the heat loss mechanism (Deacon et al, 1994;Dorsey et al, 1999;Gilbert et al, 1999;Krauchi et al, 1999). Furthermore, physiological sleepiness has been shown to cause a decrease in psychomotor performance (De Gennaro et al, 2001;De Valck and Cluydts, 2001;Hood and Bruck, 1996;Kinnari et al, 2000;Nakano et al, 2000;Nave et al, 2002;Porcu et al, 1998;Schulz et al, 1997;Thomas et al, 2000;Wesensten et al, 2002).…”

A Critical Review of Techniques Aiming at Enhancing and Sustaining Worker's Alertness during the Night Shift

“…Convergent studies have shown the positive effects of caffeine on alertness and performance during daytime as well as during night time [46][47][48][49] . These effects can be felt as soon as a moderate amount of caffeine (between 2 and 4 mg/kg) is taken, whatever its shape (coffee, tea or energy drink) 50) .…”

Effects of 28-days ingestion of a slow-release energy supplement versus placebo on hematological and cardiovascular measures of health

“…The efficacy of the delivery of slow-release caffeine alone is fairly well documented [3,[21][22][23]. However, an assessment of safety and tolerability of prolonged use of slow-release energy supplements is lacking.…”