Effects of caffeine on alertness as measured by infrared reflectance oculography

Abstract

The results demonstrated that despite being well rested, administration of caffeine significantly increased alertness and enhanced performance, and these changes were able to be detected with the JDS.

Effects of caffeine on sleep and cognition

“…Self-reports of sleepiness were not as sensitive; differences between the caffeine and placebo condition were only observed 30 min after substance administration. These findings support the conclusion that caffeine can have beneficial effects on performance and alertness (Michael et al, 2008), and that these effects do not seem to be related to withdrawal or withdrawal reversal since it is unlikely that tolerance has developed in the individuals who did not consume caffeine on a regular base.…”

“…In contrast with the outcome of the Keane and James (2008) study, the result of Michael et al (2008) showed that, even though the participants were well rested, caffeine was able to reduce drowsiness, as deduced from ocular movements and reaction times, and these changes persisted for 3-4 h. The use of different ocular variables seemed to provide a sensitive measure to detect subtle changes in alertness induced by caffeine. Self-reports of sleepiness were not as sensitive; differences between the caffeine and placebo condition were only observed 30 min after substance administration.…”

“…In order to avoid confounding of caffeine effects with tolerance or withdrawal, Michael et al (2008) examined the effects of caffeine in 12 participants (age 18-29 years), who consumed either no caffeine or very little caffeine on a regular basis. The wellrested participants were tested on 2 separate days, using vigilance tests scheduled at baseline (around 9.00 a.m.) and at 30, 60, 120, 180, and 240 min after placebo or caffeine (200 mg) administration.…”

Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day

“…Even at low doses, caffeine results in significant increases in firing rates in regions mediating sleep and mood, such as the dorsal and medial raphe nuclei and the locus coeruleus (Nehlig and Boyet, 2000). This amplified cortical activity likely underlies the increase in subjective reports of alertness (Smith, 2005; Michael et al, 2008) as well as increases in sustained attention and faster reaction times (Adan and Serra-Grabulosa, 2010; for review see: Einöther and Giesbrecht, 2012). These effects are amplified when individuals are experiencing low states of arousal as measured by subjective ratings of alertness (Brice and Smith, 2001) and sleepiness (Adan et al, 2008).…”

Comparative Bioavailability and Pharmacodynamic Aspects of Cyclobenzaprine and Caffeine in Healthy Subjects and the Effect on Drowsiness Intensity

“…In an even more recent work, Carrier et al, (2009) studied the combined influence of age and caffeine and concluded that the sleep of middle-aged subjects are particularly vulnerable to the circadian waking signal and proposed that lower brain synchronization due to age and caffeine produces greater difficulty in overriding the circadian waking signal during daytime sleep and leads to fragmented sleep. Michael et al, (2008) studied the effects of a capsule containing 200 mg of caffeine in twelve non-sleep-deprived participants. The author observed that caffeine reduced the Johns Drowsiness Scale score and reaction times, and these changes persisted for 3 to 4 h. They concluded that despite being well rested, administration of caffeine significantly increased alertness and enhanced performance.…”