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Caffeine as an attention enhancer: Reviewing existing assumptions
Abstract and Figures
Rationale
Despite the large number of studies on the behavioural effects of caffeine, an unequivocal conclusion had not been reached. In this review, we seek to disentangle a number of questions.
Objective
Whereas there is a general consensus that caffeine can improve performance on simple tasks, it is not clear whether complex tasks are also affected, or if caffeine affects performance of the three attention networks (alerting, orienting and executive control). Other questions being raised in this review are whether effects are more pronounced for higher levels of caffeine, are influenced by habitual caffeine use and whether there effects are due to withdrawal reversal.
Method
Literature review of double-blind placebo controlled studies that assessed acute effects of caffeine on attention tasks in healthy adult volunteers.
Results
Caffeine improves performance on simple and complex attention tasks, and affects the alerting, and executive control networks. Furthermore, there is inconclusive evidence on dose-related performance effects of caffeine, or the influence of habitual caffeine consumption on the performance effects of caffeine. Finally, caffeine’s effects cannot be attributed to withdrawal reversal.
Conclusions
Evidence shows that caffeine has clear beneficial effects on attention, and that the effects are even more widespread than previously assumed.
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... Consumption caffeine was found to decrease the risk of developing or preventing some types of cancer and neurodegenerative diseases such as Alzheimer's disease (Arab, 2010;Ross et al., 2000) [8,9] However, consuming high dosages of caffeine beverages could lead to adverse effects on human health such as headache, sleep disorders, anxiety, tachycardia, and high blood pressure (Temple et al., 2017) [10]. Also, caffeine could lead to physical dependency, which may cause a decreasing in human performance during withdrawal stage (O'Callaghan et al., 2018) [11]. ...
... Also, three online survey studies showed there was no significant correlation between caffeine intake and academic performance (Bindbeutel, 2016;Khan et al., 2017;Pattison et al., 2016) [17,18,19] In addition, Gabrish 2017 presented in her thesis that students who were not caffeine consumers had higher GPA comparing to coffee consumers (Pattison et al., 2016) [19]. One of the explanation why caffeine intake does not improve the academic performance is that caffeine disrupt the sleep(Gabrish, 2017; O'Callaghan et al., 2018) [11,20]. ...
... The participants in this study slept less hours after drinking coffee. The literature supports that caffeine affects the sleep quality and it leads to sleep deprivation (Gabrish, 2017; O'Callaghan et al., 2018) [11,20]. Caffeine works on the receptors A1 and A2A, which affects the brain function associated with sleep, arousal, and cognition (Clark & Landolt, 2017) [21]. ...
Background: caffeine can be found in many types of food and beverages such as coffee beans, chocolates, and tea. Caffeine consumption could be used for different reasons. For example, healthcare providers use caffeine to reduce fatigue and cope with demanding workloads. The aim of this study is to estimate the effect of caffeine consumption on exam performance among universities students. Methodology: The study used a cross-sectional design. Students at The Hashemite University in Zarqa-Jordan from both sexes were eligible to participate by completing an electronic questionnaire. Results: A total of 145 participants participated in the study, 113 (80.7%) participants reported a usual drinking of 1-2 coffee cups per day. Most of participants (48.6%) reported that the usually sleep >7 hours when they do not drink coffee. While most of participants (40%) reported 5-7 hours of sleep when they drink coffee. Conclusion: We concluded that caffeine intake decreases the amount of sleeping hours by 2 or more hours during night for students and this effect on their concentration, but on the other hand the student’s feels more energy after drinking caffeine and this helps them to feel more awake.
... For instance, van den Berg et al. [54] used 3 mg per kg of body weight, while Lanini et al. [71] calculated personalized doses for each participant based on their daily caffeine habits (25-300 mg). In previous research, faster RT was generally observed after a medium to high dose (150-450 mg), while greater accuracy was associated with a low dose of caffeine (50-150 mg [72]. In the present study, we chose a dose of 200 mg of caffeine, which falls in the range that both accuracy and RT may be facilitated, and which is approximately equal to two 16 oz cups of regular coffee [73]. ...
... With regard to flavanols, dosages in the range of 83-994 mg have produced acute effects in previous studies [24,27]. Similarly, with regard to caffeine, dosages in the range of 60-450 mg have been considered as effective previously, particularly on attention-related functions [72], with limited evidence for dose-dependency within this range. More recently, a dose-dependent range between 40 and 300 mg has been identified as effective in improving attentional, and less consistently, memory-related processes in well-rested individuals [5]. ...
... Furthermore, it might be advisable to target specific groups that perform at a lower baseline level than our healthy young university students did, such as elderly, fatigued, or sleep-deprived individuals. Finally, we did not strictly control the (habitual) intake of flavanols and caffeine, which would also be advisable to assess possible contributions of withdrawal effects, which has been a concern in the caffeine literature in particular (e.g., [48],but see also [72]). ...
Purpose
Consumption of cocoa flavanols and caffeine might acutely enhance cognition, particularly in synergy. Due to the use of multifaceted tasks in prior research, it is unclear precisely which cognitive functions are implicated. Here we aimed to assess the acute effects of the (joint) ingestion of cocoa flavanols and caffeine on temporal attention, spatial attention, and working memory.
Methods
In four separate sessions of a randomized, double-blind, placebo-controlled, crossover trial, 48 young adult participants consumed a placebo drink, a cocoa flavanols (415 mg) drink, a caffeine (215 mg) drink, and a drink containing both concurrently. In each session, after ingestion, we tested performance in three cognitive tasks. We tested temporal attention in a dual-target rapid serial visual presentation paradigm, known to elicit the attentional blink, in which the time between the targets was manipulated. We measured spatial attention in a visual search task, where we varied the number of distractors that appeared simultaneously with the target. We tested working memory in a delayed recall task, in which the number of stimuli to be remembered was manipulated.
Results
We obtained the expected performance pattern in each task, but found no evidence for modulation of response accuracy or reaction times by the ingestion of either substance, nor of their combined ingestion, even in the most challenging task conditions.
Conclusions
We conclude that, even when jointly ingested, neither the tested amount of cocoa flavanols nor caffeine have acute effects that are robustly measurable on cognitive tasks that target attention and working memory specifically.
... Similarly, several studies have been highlighted and supported the view according to which caffeine exerts alerting influences on rapid information processing and continuous attention tasks with performance improvements after its administration (see McLellan et al., 2016 for a review). Caffeine delivering to both sleep-deprived and rested people, in doses ranging from 12.5 to 400 mg, seems to reduce reaction times as well as exert positive effects on both simple and complex attention tasks (Einöther & Giesbrecht, 2013). ...
... Caffeine impact on executive functions is still under debate due to both a relatively small number of published studies and the wide-ranging employing of materials and methods (McLellan et al., 2016), which lead to conflicting findings. In fact, while some studies have been found caffeine enhancement effects in several cognitive domains, such as task switching and anticipatory control processes (Tieges et al., 2006), monitoring of ongoing cognitive processes (Tieges et al., 2004), executive updating (Lanini et al., 2016), executive and inhibitory control (e.g., Einöther & Giesbrecht, 2013), others failed to find any effects (e.g., Tieges et al., 2009) or just revealed influences in light caffeine consumers after the ingestion of a relatively large dose (e.g., Lyvers et al., 2004). Recently, Soar et al. (2016), by using a novel ecologically valid virtual reality task, the Jansari assessment of Executive Functions, revealed performance improvements on planning, prospective memory, and creative thinking following caffeinated coffee relative to the decaffeinated coffee ingestion, suggesting that executive functioning enhancements after a dose of caffeine may only be spotted through more ecological and valid tasks. ...
Coffee and caffeinated products have a remarkable potential to beneficially influence different psychomotor variables. The main neuropharmacological mechanisms underlying caffeine’s psychostimulant action involve an antagonist role on the adenosine receptor, which enables an increase of brain catecholamine levels. These mechanisms also encompass dependence and withdrawal effects. Concerning the impact on mood, caffeine increases attention, alertness, hedonic tone, vigor, and motivation, whereas it decreases apathy, irritability, anxiety, and tiredness. The effects on cognition are featured by a positive influence on low-order cognitive functions such as processing speed (reaction times) or prolonged vigilance, whereas the ones on higher-order cognitive functions such as planning, conceptualizing, managing, and working memory are still under debate although with positive promises. Caffeine exerts also clear positive effects on physical activity, where it provides an ergogenic gain for endurance exercise and to a lesser degree also for short intense exercise. Dose dependence of the effects as well as the influence of contextual and subjective variables on caffeine’s psychomotor effects is discussed.
... In presented as the mean ± SD of the evaluation from 0 to 10 (0 = "none" or 10 = "the maximum") for each cognitive variable analysed. complex attention tasks [65] which could be attributed to its antagonistic effect on the adenosine receptor [64]. However, other studies did not support a significant caffeine effect on attention [66,67]. ...
Purpose
Caffeine is a potent central nervous system stimulant that increases the activity of the prefrontal cortex and can improve various cognitive skills. An improvement in these cognitive skills can lead to further benefits in athletic performance. Therefore, it is necessary to clarify the dose-response of caffeine on cognitive performance. This study aimed to determine the effects of different doses of caffeine on sport-related cognitive aspects.
Methods
Twenty-nine healthy physically active young adults were recruited. All participants completed three trials under the following conditions: (a) placebo, (b) 3 mg/kg, or (c) 6 mg/kg body mass of caffeine. In each trial, different cognitive abilities were evaluated with the following battery of tests: reaction time (Dynavision™ D2), anticipation (Bassin Anticipation Timer), sustained attention (Go/No-Go and Eriksen Flanker Test) and memory tests. Moreover, the side effects and the perceived sensation index were recorded 24 h after each test.
Results
Reaction time only improved following 6 mg/kg of caffeine intake (Physical reaction time: -0.04 s, 95% CI -0.08 to -0.01 s, P = 0.036, d = 0.5; Motor reaction time: -0.04 s, 95% CI -0.07 to -0.01 s, P = 0.008, d = 0.6) compared to the placebo condition. Anticipation, sustained attention, and memory were not affected after either caffeine dose intake (all P > 0.05). In addition, the 6 mg/kg dose of caffeine augmented the occurrence of the side effects of increased activeness (P = 0.046) and nervousness (P = 0.001).
Conclusion
Acute intake of 6 mg/kg caffeine is effective in improving reaction time despite increasing the occurrence of side effects in healthy physically active young adults.
Study registration
This study has been registered in ClinicalTrials whose ID is: NCT05995314 (2023-08-08).
... It is worth noting that smoking increases the primary pathway for caffeine metabolism, suggesting that smokers may need to consume more caffeine to achieve the same effects as non-smokers [10]. The motivation to experience both the benefits of daytime alertness and a good subjective quality of sleep despite prior stimulant use likely explains the typical pattern of caffeine consumption in the morning and afternoon [11,12]. ...
Background: Caffeine is a commonly consumed psychoactive substance with potential effects on sleep quality. However, few studies have examined this relationship in the general population of Makkah, Saudi Arabia.
Objective: To investigate the impact of caffeine consumption on sleep quality and identify demographic factors associated with caffeine intake and sleep quality in Makkah's general population.
Methods: This cross-sectional study used a convenient sampling approach to recruit 390 individuals residing in Makkah. Data were collected via a Google Forms questionnaire distributed through various social media platforms. Caffeine intake and sleep quality were assessed using a validated questionnaire adapted for Saudi Arabia and the Pittsburgh Sleep Quality Index (PSQI), respectively.
Results: The median total daily caffeine intake was 324.20 mg, with 43.1% of participants consuming more than the suggested cutoff of 400 mg daily. There were significant positive correlations between PSQI and total caffeine consumption in the morning, evening, and overall daily consumption. The results also indicated significant relationships between demographic factors, such as marital status, educational level, income, and BMI groups, and caffeine consumption.
Conclusion: Caffeine intake was found to be high among the general population of Makkah, with a significant portion consuming more than the suggested daily limit. There was a significant positive correlation between caffeine consumption and poor sleep quality. Additionally, demographic factors such as marital status, educational level, income, and BMI groups were found to be associated with caffeine consumption.
Introduction: Caffeine and nicotine are widely consumed legal stimulants with significant public health implications, particularly among youth. To investigate addiction and usage patterns among young males. This study focuses on how these two drugs, nicotine and caffeine alter brain and body functioning. Methods: This research encompassed two phases: Phase 1, involved questionnaire data collection and behavioral analysis. In Phase 2, biochemical effects of nicotine and caffeine addiction were assessed via blood sample or biochemical analysis. Results: The outcome of this study indicates that fasting blood glucose as well as blood cholesterol for the addicted group (nicotine and caffeine users) was significantly higher than that of the non-addicts. The study analyzed biomarker changes in male individuals with nicotine and caffeine addiction, compared to non-addicts. Nicotine addicts showed significantly higher cholesterol (214.93 mg/dl) and glucose levels (113.20 mg/dl) compared to non-addicts (cholesterol: 107.4 mg/dl, glucose: 87.43 mg/dl). Similarly, caffeine addicts had elevated cholesterol (202.04 mg/dl) and glucose levels (113.14 mg/dl) compared to non-addicts. Conclusion: Nicotine and Caffeine consumption by young people has increased dramatically over the last decade, as both the drugs are legal and freely available. Both are addictive and can lead to adverse effects. Nicotine's addictive nature rivals: heroin and cocaine, making quitting challenging, while caffeine addiction, though less severe, also causes withdrawal symptoms but is comparatively easier to overcome.
Introduction:Caffeine is a chemical and edible substance, which is found in some foods, such as coffee, cocoa, cola, tea, chocolate and some drinks. Caffeine is the most widely used drug among people and almost 90 percent of people are using it on a daily basis. Given that taking food and drinks containing caffeine including chocolate, tea and coffee is very high in Iran as well as its effects on cardiovascular disease is still not fully understood; hence, the purpose of this research was to study the effects of caffeine on cardiovascular diseases and to report the results of research conducted in this regard.Research Methodology: In this study, library collection, searching the scientific literature and papers were used. The views of relevant experts were also examined.Results:The results showed that using tea has no harmful effects on the cardiovascular system. According to obtained results chocolate consumption will reduce both systolic and diastolic blood pressure. In general, drinking coffee causes increased blood pressure, irregular heartbeat, increased blood cholesterol, increased levels of homocysteine and increased risk of heart attacks. Several studies indicated fetal cardiac arrhythmias caused by excessive consumption of caffeine in pregnant women.Conclusions: According to the results, green and black tea has no harmful effects on cardiovascular diseases, but in some cases positive effects have also been reported. Consumption of chocolate, cocoa and coffee have harmful effects on the cardiovascular system. Due to the effects of caffeine on pregnant women, consumption of coffee and caffeine should be reduced during pregnancy.
A neglected question regarding cognitive control is how control processes might detect situations calling for their involvement. The authors propose here that the demand for control may be evaluated in part by monitoring for conflicts in information processing. This hypothesis is supported by data concerning the anterior cingulate cortex, a brain area involved in cognitive control, which also appears to respond to the occurrence of conflict. The present article reports two computational modeling studies, serving to articulate the conflict monitoring hypothesis and examine its implications. The first study tests the sufficiency of the hypothesis to account for brain activation data, applying a measure of conflict to existing models of tasks shown to engage the anterior cingulate. The second study implements a feedback loop connecting conflict monitoring to cognitive control, using this to simulate a number of important behavioral phenomena.
There is a large literature on the effects of caffeine on performance. Most of the studies have been conducted in the laboratory and further information is required on the effects of caffeine consumption on performance and safety at work.
The present studies aimed to determine whether the level of caffeine consumption influenced changes in alertness and performance over the working day. Secondary analyses of a large epidemiological database were also conducted to examine associations between caffeine consumption and cognitive failures and accidents at work.
In the first study 110 volunteers, all of whom were regular caffeine consumers, rated their alertness and carried out a simple reaction time task before and after work on a Monday and Friday. Caffeine consumption during the day was recorded and volunteers were sub-divided into low and high consumers on the basis of a median split (220 mg/day). The second study involved secondary analyses of a database formed by combining the Bristol Stress and Health at Work and Cardiff Health and Safety at Work studies. In the first analyses associations between caffeine consumption and frequency of cognitive failures were examined in a sample of 1253 white-collar workers. The second set of analyses examined associations between caffeine consumption and accidents at work in a sample of 1555 workers who were especially at risk of having an accident.
The results from the first study showed that those who consumed higher levels of caffeine reported significantly greater increases in alertness over the working day and a significantly smaller slowing of reaction time. The results from the second study demonstrated significant associations between caffeine consumption and fewer cognitive failures and accidents at work. After controlling for possible confounding factors it was found that higher caffeine consumption was associated with about half the risk of frequent/very frequent cognitive failures and a similar reduction in risk for accidents at work.
Overall, the results from the three analyses show that caffeine consumption may have benefits for performance and safety at work.
The medial frontal cortex, especially the anterior cingulate cortex (ACC), is involved in action monitoring. We studied the role of moderate amounts of caffeine in action monitoring as expressed by the error-related negativity (ERN), an event-related brain component that reflects ACC activity. In a double-blind, placebo-controlled, within-subjects experiment, two caffeine doses (3 and 5 mg/kg body weight) and a placebo were administered to habitual coffee drinkers. Compared with placebo, both caffeine doses enlarged the ERN. Amplitudes of the P2 and P3 components were not affected by caffeine. Thus, the enlarged ERN after caffeine reflects a specific effect on action monitoring. We conclude that consumption of a few cups of coffee strengthens central information processing, specifically the monitoring of ongoing cognitive processes for signs of erroneous outcomes. Brain areas related to action monitoring such as the ACC presumably mediate these caffeine effects. D 2004 Elsevier B.V. All rights reserved. Theme: Neural basis of behavior Topic: Cognition
Anterior cingulate cortex (ACC) is a part of the brain's limbic system. Classically, this region has been related to affect, on the basis of lesion studies in humans and in animals. In the late 1980s, neuroimaging research indicated that ACC was active in many studies of cognition. The findings from EEG studies of a focal area of negativity in scalp electrodes following an error response led to the idea that ACC might be the brain's error detection and correction device. In this article, these various findings are reviewed in relation to the idea that ACC is a part of a circuit involved in a form of attention that serves to regulate both cognitive and emotional processing. Neuroimaging studies showing that separate areas of ACC are involved in cognition and emotion are discussed and related to results showing that the error negativity is influenced by affect and motivation. In addition, the development of the emotional and cognitive roles of ACC are discussed, and how the success of this regulation in controlling responses might be correlated with cingulate size. Finally, some theories are considered about how the different subdivisions of ACC might interact with other cortical structures as a part of the circuits involved in the regulation of mental and emotional activity.
The medial frontal cortex, especially the anterior cingulate cortex (ACC), is involved in action monitoring. We studied the role of moderate amounts of caffeine in action monitoring as expressed by the error-related negativity (ERN), an event-related brain component that reflects ACC activity. In a double-blind, placebo-controlled, within-subjects experiment, two caffeine doses (3 and 5 mg/kg body weight) and a placebo were administered to habitual coffee drinkers. Compared with placebo, both caffeine doses enlarged the ERN. Amplitudes of the P2 and P3 components were not affected by caffeine. Thus, the enlarged ERN after caffeine reflects a specific effect on action monitoring. We conclude that consumption of a few cups of coffee strengthens central information processing, specifically the monitoring of ongoing cognitive processes for signs of erroneous outcomes. Brain areas related to action monitoring such as the ACC presumably mediate these caffeine effects.
This study examined the effects of breakfast cereal and caffeinated coffee on working memory, attention, mood, and cardiovascular function. One hundred and forty-four volunteers (72 male, 72 female, mean age 21 years) were assigned to one of the groups formed by combining breakfast (cereal versus no breakfast) and caffeine (caffeinated versus decaffeinated coffee) conditions. The volunteers completed a baseline session between 0800 and 0845 h. The breakfast/caffeine administration took place between 0845 and 0915 h. They then completed another test session (starting at 0945) and had a coffee break at 1045, followed by a final session starting at 1145. The results showed that those who consumed breakfast cereal had a more positive mood at the start of the test sessions, performed better on a spatial memory task, and felt calmer at the end of the test session than those in the no breakfast condition. Ingestion of caffeine had no effect on initial mood or working memory, but it did improve encoding of new information and counteracted the fatigue that developed over the test session. Caffeine increased blood pressure and pulse rate, whereas breakfast cereal consumption only had an effect on pulse. Overall, these results confirm previous findings on the effects of breakfast and caffeine, and demonstrate distinct profiles for two common examples of early-morning food and drink, breakfast cereal and caffeinated coffee.
An experiment was conducted to examine the effects of caffeine and noise on mood, mental performance and cardiovascular function. One hundred and six young adults (mean age 21·2 years) took part in the study. Subjects were assigned to one of six groups formed by combining noise/quiet and drink (caffeinated coffee, decaffeinated coffee and fruit juice) conditions. Subjects were familiarized with the tasks and then completed a pre-drink baseline session (conducted in the quiet). Subjects were then given either caffeinated coffee (1·5 mg/kg caffeine), decaffeinated coffee or fruit juice. Following consumption of the drink subjects were re-tested 1 h later, either in noise (75 dBA conglomerate noise, consisting of speech, music and machinery noise) or in quiet. The subjects exposed to noise felt more anxious and showed an increase in blood pressure. Their performance of a cognitive vigilance task also declined over time. There were no significant main effects of caffeine, although simple reaction time was quickest in the caffeinated coffee group. Caffeine did not modify the effects of noise on mood, cardiovascular functioning or sustained attention. Indeed, the only interaction between drinks and noise was found in recall and recognition memory tasks, with the caffeine/noise group having better memory performance than the decaffeinated/noise subjects. Overall, the results show that low levels of caffeine do not increase the behavioural and physiological changes observed in a stressful situation. © 1997 John Wiley & Sons, Ltd.
Summary Caffeine is the most popular drug in the world. After consumption, it is rapidly distributed throughout the body where it acts by blocking the action of endogenous adenosine at adenosine A1 and A2a receptors, resulting in a variety of physiological effects. Although it is valued as a useful psychostimulant, recent evidence suggests that actually little or no acute benefit is gained from regular caffeine consumption. This is because withdrawal of caffeine (e.g. overnight) lowers alertness and mood and degrades performance, and while consumption of some more caffeine reverses these effects, it does not boost functioning to above ‘normal’ levels. It also tends to increase anxiety, particularly in susceptible individuals. In contrast, caffeine consumption may separately lower the risk of cognitive decline in older age, perhaps owing to effects involving neuroprotective functions of the adenosine system. Currently, however, not enough is known to do a full risk assessment on these or other potential health effects of dietary caffeine.