A review of caffeine’s effects on cognitive, physical and occupational performance

Abstract

Caffeine is consumed by over 80% of U.S. adults. This review examines the effects caffeine has on cognitive and physical function, since most real-world activities require complex decision making, motor processing and movement. Caffeine exerts its effects by blocking adenosine receptors. Following low (∼40mg or ∼0.5mgkg) to moderate (∼300mg or 4mgkg) caffeine doses, alertness, vigilance, attention, reaction time and attention improve, but less consistent effects are observed on memory and higher-order executive function, such as judgment and decision making. Effects on physical performance on a vast array of physical performance metrics such as time-to-exhaustion, time-trial, muscle strength and endurance, and high-intensity sprints typical of team sports are evident following doses that exceed about 200mg (∼3mgkg). Many occupations, including military, first responders, transport workers and factory shift workers, require optimal physical and cognitive function to ensure success, workplace safety and productivity. In these circumstances, that may include restricted sleep, repeated administration of caffeine is an effective strategy to maintain physical and cognitive capabilities.

Caffeine and energy drink use by combat arms soldiers in Afghanistan as a countermeasure for sleep loss and high operational demands

“…About 80% of the U.S. population regularly consume caffeine. 1 Many studies have examined the behavioral effects of caffeine, and it is generally agreed that in moderate doses it enhances specific aspects of cognitive performance, including vigilance and attention, as well as decreasing selfreported fatigue (for comprehensive reviews see [2][3][4][5] ).…”

A Combination of Nootropic Ingredients (CAF+) Is Not Better than Caffeine in Improving Cognitive Functions

“…The dose used for the caffeine capsule (100 mg) is in the range of the reported cognition-enhancing effects (McLellan et al 2016). The same dose was used for the CAF+ formulation.…”

Effect of caffeine on maximal oxygen uptake in wheelchair rugby players: A randomized, placebo-controlled, double-blind study

“…Adenosine antagonism in adipocytes clearly leads to increased lipolysis and an increase in plasma free fatty acid concentration. Caffeine also slightly increases heart rate and myocardial contractility (McLellan et al, 2016). Goldstein et al (2010) in its general review, which evaluated the results of 97 studies on the effect of caffeine during exercise, show that caffeine supplementation helps maintain maximum endurance performance, and is highly effective in intermittent performance.…”

“…It is also necessary to draw attention to the potential health risks of caffeine use. Using high doses can cause insomnia, digestive problems or headache (McLellan et al, 2016).…”