Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms these measures in medium-high-high consumers, but, apart from decreasing sleepiness, had 40 little effect on them in non-low consumers. The failure of caffeine to increase mental 41 alertness and improve mental performance in non-low consumers was related to a substantial 42 caffeine-induced increase in anxiety/jitteriness that offset the benefit of decreased sleepiness. 43Caffeine enhanced physical performance (faster tapping speed and faster simple and choice 44 reaction times) in both medium-high and non-low consumers. Conclusions While caffeine 45 benefits motor performance and tolerance develops to its tendency to increase 46 anxiety/jitteriness, tolerance to its effects on sleepiness means that frequent consumption fails 47 to enhance mental alertness and mental performance. 48 49

Effects of anxiety sensitivity and expectations on the modulation of the startle eyeblink response during a caffeine challenge

“…Further interoceptive challenge studies are required that replicate and strengthen the current evidence by simultaneously measuring both the startle eyeblink response and eventrelated potentials to startle probes. Additionally, as habitual caffeine consumers might have acquired tolerance to the effect of caffeine, firstly, reversal of withdrawal symptoms including aversive bodily sensations possibly masked effects; secondly, compared to various challenge tests (hyperventilation, CO 2 inhalation) caffeine may provoke only mild interoceptive stimulation which rendered it difficult to reveal pronounced anxiety induction (Rogers et al 2010;Rogers et al 2013). In conclusion, subsequent studies investigating the effect of caffeine administration should take into account the effects of expectancy and anxiety sensitivity.…”

“…Moreover, we expected to observe an increase of startle response magnitudes after caffeine consumption, which has been attributed to its arousalinducing effects (Andrews et al 1998;Flaten et al 2003;Flaten and Blumenthal 1999). On a subjective level, the ingestion of caffeine was expected to lead to an increase in arousal and alertness (Flaten and Blumenthal 1999;Mikalsen et al 2001;Rogers et al 2013).…”

Bioactive Micronutrients in Coffee: Recent Analytical Approaches for Characterization and Quantification

“…Withdrawal from caffeine ingestion may present with lower mental alertness, diminished performance, and over sleepiness [45]. …”

Acute effects of caffeine supplementation on cortical arousal, anxiety, physiological response and marksmanship in close quarter combat

“…It has been demonstrated that caffeine is an anxiogenic substance (Rogers et al 2013), which means its use in combat could be prejudicial and dangerous, but nevertheless it is a substance widely used by soldiers. In addition, short weapons, such as pistols, have traditionally been used in CQC because is characterized by occurring at a close distance.…”