The effect of caffeine on human performance, alone and in combination with ethanol

Franks, H. M.; Hagedorn, Hans Christian; Hensley, V. R.; Hensley, W.J.; Starmer, G. A.

doi:10.1007/bf00429058

Cited by 103 publications

(70 citation statements)

References 10 publications

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“…The reported effect of caffeine on psychomotor function is somewhat conflicting (21,24,35), but, in this study, there was no indication that caffeine improved either reaction or movement times. The frequency of withdrawal symptoms (20,22,40) and side effects (21, 24) associated with caffeine, as well as the impaired postural stability (10,41), are in accordance with previous findings. Thus in one study by Franks et al (10), body sway was significantly increased in the young subjects 40 min after ingesting 4.3 mg/kg caffeine, and also elderly subjects in a study by Swift and Tiplady (41) showed an increased body sway on caffeine compared with placebo.…”

Section: Discussionsupporting

confidence: 91%

“…The frequency of withdrawal symptoms (20,22,40) and side effects (21, 24) associated with caffeine, as well as the impaired postural stability (10,41), are in accordance with previous findings. Thus in one study by Franks et al (10), body sway was significantly increased in the young subjects 40 min after ingesting 4.3 mg/kg caffeine, and also elderly subjects in a study by Swift and Tiplady (41) showed an increased body sway on caffeine compared with placebo. In this study, postural stability was impaired by 25 and 45% with eyes opened and closed, respectively.…”

Section: Discussionsupporting

confidence: 91%

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Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study

Nørager

Jensen

Madsen³

et al. 2005

Journal of Applied Physiology

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Norager, C. B., M. B. Jensen, M. R. Madsen, and S. Laurberg. Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study. J Appl Physiol 99: 2302-2306, 2005. First published August 4, 2005 doi:10.1152/japplphysiol.00309.2005.-This study investigated the effect of caffeine on physical performance in healthy citizens aged Ն70 yr. The randomized, double-blind, placebo-controlled, crossover study was conducted in 15 men and 15 women recruited by their general practitioner. Participants abstained from caffeine for 48 h and were randomized to receive one capsule of placebo and then caffeine (6 mg/kg) or caffeine and then placebo with 1 wk in between. One hour after intervention, we measured reaction and movement times, postural stability, walking speed, cycling at 65% of expected maximal heart rate, perceived effort during cycling, maximal isometric arm flexion strength, and endurance. Analysis was by intention to treat, and P Ͻ 0.05 was regarded as significant. Caffeine increased cycling endurance by 25% [95% confidence interval (CI): 13-38; P ϭ 0.0001] and isometric arm flexion endurance by 54% (95% CI: 29 -83; P ϭ 0.0001). Caffeine also reduced the rating of perceived exertion after 5 min of cycling by 11% (95% CI: 5-17; P ϭ 0.002) and postural stability with eyes open by 25% (95% CI: 2-53; P ϭ 0.03). Caffeine ingestion did not affect muscle strength, walking speed, reaction, and movement times. At the end of the study, 46% of participants correctly identified when they received caffeine and placebo. Caffeine increased exercise endurance in healthy citizens aged Ն70 yr, but the participants' reasons for stopping the test may have varied between subjects, as the cycling test was done at ϳ55% of maximal oxygen consumption. Further studies are required to investigate whether caffeine can be utilized to improve the physical performance of elderly citizens. fatigue; perceived exertion; postural stability; elderly CAFFEINE INGESTION INCREASES the endurance of young people exercising at 60 -85% of their maximal oxygen uptake (12,13,38). It also seems to improve endurance as measured by repeated submaximal isometric contraction (34) and decreases the rate of perceived exertion during exercise (6, 9, 37). Typically, doses of ϳ6 mg/kg caffeine (equivalent to 4 cups of coffee) were used in these studies.With a growing number of elderly with a physically active lifestyle and many elderly participating in rehabilitation programs, the endurance-enhancing effect of caffeine is of increasing interest in this age group. However, the enduranceenhancing effect of caffeine found in young subjects has not previously been examined in the elderly.The aim of this study was to investigate whether 6 mg/kg caffeine improves physical performance and reduces the perceived effort during work in healthy citizens aged Ն70 yr. The main hypothesis was that caffeine would improve cycling endurance at 65% of expected maximal heart rate, and the secondary hypothesis was that caffeine would improv...

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 91%

Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study

Nørager

Jensen

Madsen³

et al. 2005

Journal of Applied Physiology

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“…Acute exposure to ethanol inhibits adenosine re-uptake via a facilitative nucleoside transporter, increasing the extracellular concentration of adenosine (Nagy et al, 1990;Krauss et al, 1993). In humans, the nonselective adenosine receptor antagonist caffeine reduces sleepiness and psychomotor performance impairment produced by moderate-to-high ethanol doses (Franks et al, 1975;Fillmore and Vogel-Sprott, 1995;Liguori and Robinson, 2001;Drake et al, 2003). In rodents, adenosine receptors seem to modulate some of the pharmacological properties of ethanol, such as sedative/ hypnotic effects (El Yacoubi et al, 2003), motor incoordination (Meng and Dar, 1995;Barwick and Dar, 1998;Dar, 2001), and development of rapid tolerance to ethanolinduced motor impairments (Batista et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Acute exposure to ethanol increases the concentration of extracellular adenosine (Nagy et al, 1990;Krauss et al, 1993). Moreover, there is considerable evidence that the co-administration of caffeine (a nonselective adenosine receptor antagonist) can reduce sleep and psychomotor performance impairment associated with moderate-to-high ethanol doses in humans (Franks et al, 1975;Fillmore and Vogel-Sprott, 1995;Liguori and Robinson, 2001;Drake et al, 2003). Furthermore, the combined administration of caffeine and alcohol can increase the development of alcohol tolerance (Fillmore, 2003).…”

Section: Introductionmentioning

confidence: 99%

Activation of Adenosine A1 Receptors Reduces Anxiety-Like Behavior During Acute Ethanol Withdrawal (Hangover) in Mice

Prediger

Silva

Batista

et al. 2006

Neuropsychopharmacol

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Elevated signs of anxiety are observed in both humans and rodents during withdrawal from chronic as well as acute ethanol exposure, and it represents an important motivational factor for ethanol relapse. Several reports have suggested the involvement of brain adenosine receptors in different actions produced by ethanol such as motor incoordination and hypnotic effects. In addition, we have recently demonstrated that adenosine A 1 receptors modulate the anxiolytic-like effect induced by ethanol in mice. In the present study, we evaluated the potential of adenosine A 1 and A 2A receptor agonists in reducing the anxiety-like behavior during acute ethanol withdrawal (hangover) in mice. Animals received a single intraperitoneal administration of saline or ethanol (4 g/kg) and were tested in the elevated plus maze after an interval of 0.5-24 h. The results indicated that hangover-induced anxiety was most pronounced between 12 and 18 h after ethanol administration, as indicated by a significant reduction in the exploration of the open arms of the maze. At this time interval, ethanol was completely cleared. The acute administration of 'nonanxiolytic' doses of adenosine and the selective adenosine A 1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA), but not the adenosine A 2A receptor agonist N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl]adenosine (DPMA), at the onset of peak withdrawal (18 h), reduced this anxiogenic-like response. In addition, the effect of CCPA on the anxiety-like behavior of ethanol hangover was reversed by pretreatment with the selective adenosine A 1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). These results reinforce the notion of the involvement of adenosine receptors in the anxiety-like responses and indicate the potential of adenosine A 1 receptor agonists to reduce the anxiogenic effects during ethanol withdrawal.

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“…Caffeine has been shown to reduce simple RT and to improve performance on the SVT (e.g., Warburton 1995;Smith et al 1992;Smit and Rogers 2000;Hewlett and Smith 1999). Alcohol typically lengthens simple RT (e.g., Carpenter 1959;Sutton and Burns 1971;Franks et al 1975;Tzambazis and Stough 2000), although doses below 0.3 mg/kg might speed responding (Lloyd and Rogers 1997). Alcohol might be expected to disrupt SVT performance, at least at higher doses.…”

Section: Introductionmentioning

confidence: 99%

Dissociations between motor timing, motor coordination, and time perception after the administration of alcohol or caffeine

et al. 2008

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Rationale The impacts of psychoactive drugs on timing have usefully informed theories of timing and its substrates. Objectives The objectives of the study are to test the effects of alcohol and caffeine on the explicit timing involved in tapping with the implicit timing observed in the coordinated picking up of an object, and with the temporal discrimination. Materials and methods Participants in the "alcohol" experiment (N=16) received placebo, "low" (0.12 g/kg or 0.14 g/kg for women/men, respectively) or "high" (0.37 g/kg or 0.42 g/kg, respectively) doses of alcohol, and those in the "caffeine" experiment (N=16) received placebo, 200 or 400 mg caffeine. Time production variability was measured by repetitive tapping of specified intervals, and sources of variance attributable to central timer processes and peripheral motor implementation were dissociated. The explicit timing in tapping was compared with the implicit timing in the coordinated picking up of an object. Time perception was measured as discrimination thresholds for intervals of similar duration. Drug effects on reaction time were also measured. Results For tapping, alcohol significantly increased timer variability, but not motor variability; it did not affect coordination timing in the grip-lift task. Conversely, for time perception, the low dose of alcohol improved temporal discrimination. Caffeine produced no effects on any of the timing tasks, despite significantly reducing reaction times. Conclusions The effects of alcohol argue against a common clock process underlying time interval perception and production in the range below 1 s. In contrast to reaction time measures, time perception and time production appear relatively insensitive to caffeine.

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The effect of caffeine on human performance, alone and in combination with ethanol

Cited by 103 publications

References 10 publications

Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study

Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study

Activation of Adenosine A1 Receptors Reduces Anxiety-Like Behavior During Acute Ethanol Withdrawal (Hangover) in Mice

Dissociations between motor timing, motor coordination, and time perception after the administration of alcohol or caffeine

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