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Current Neuropharmacology Jan 2015Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and... (Meta-Analysis)
Meta-Analysis Review
Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine's mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine's interaction with other substances or to the individuals' preexisting metabolism alterations or diseases.
Topics: Athletic Performance; Caffeine; Central Nervous System Stimulants; Drug Utilization; Humans; Nootropic Agents; Substance-Related Disorders
PubMed: 26074744
DOI: 10.2174/1570159X13666141210215655 -
Journal of the International Society of... Jan 2021Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows:... (Review)
Review
Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.
Topics: Anxiety; Athletic Performance; Caffeine; Capsules; Chewing Gum; Cognition; Cytochrome P-450 CYP1A2; Doping in Sports; Drug Dosage Calculations; Energy Drinks; Exercise; Hot Temperature; Humans; Movement; Muscle Strength; Muscle, Skeletal; Performance-Enhancing Substances; Physical Endurance; Physical Functional Performance; Receptor, Adenosine A2A; Sleep; Societies, Medical; Sports Nutritional Physiological Phenomena; Sports Nutritional Sciences
PubMed: 33388079
DOI: 10.1186/s12970-020-00383-4 -
Sports Medicine (Auckland, N.Z.) Jul 2019Caffeine is a widely utilized performance-enhancing supplement used by athletes and non-athletes alike. In recent years, a number of meta-analyses have demonstrated that... (Review)
Review
Caffeine is a widely utilized performance-enhancing supplement used by athletes and non-athletes alike. In recent years, a number of meta-analyses have demonstrated that caffeine's ergogenic effects on exercise performance are well-established and well-replicated, appearing consistent across a broad range of exercise modalities. As such, it is clear that caffeine is an ergogenic aid-but can we further explore the context of this ergogenic aid in order to better inform practice? We propose that future research should aim to better understand the nuances of caffeine use within sport and exercise. Here, we propose a number of areas for exploration within future caffeine research. These include an understanding of the effects of training status, habitual caffeine use, time of day, age, and sex on caffeine ergogenicity, as well as further insight into the modifying effects of genotype. We also propose that a better understanding of the wider, non-direct effects of caffeine on exercise, such as how it modifies sleep, anxiety, and post-exercise recovery, will ensure athletes can maximize the performance benefits of caffeine supplementation during both training and competition. Whilst not exhaustive, we hope that the questions provided within this manuscript will prompt researchers to explore areas with the potential to have a large impact on caffeine use in the future.
Topics: Adaptation, Physiological; Athletes; Athletic Performance; Caffeine; Circadian Rhythm; Exercise; Genotype; Humans; Performance-Enhancing Substances; Sex Factors; Time Factors
PubMed: 30977054
DOI: 10.1007/s40279-019-01101-0 -
Regulatory Toxicology and Pharmacology... Oct 2017This report evaluates the scientific literature on caffeine with respect to potential cardiovascular outcomes, specifically relative risks of total cardiovascular... (Review)
Review
This report evaluates the scientific literature on caffeine with respect to potential cardiovascular outcomes, specifically relative risks of total cardiovascular disease (CVD), coronary heart disease (CHD) and acute myocardial infarction (AMI), effects on arrhythmia, heart failure, sudden cardiac arrest, stroke, blood pressure, hypertension, and other biomarkers of effect, including heart rate, cerebral blood flow, cardiac output, plasma homocysteine levels, serum cholesterol levels, electrocardiogram (EKG) parameters, heart rate variability, endothelial/platelet function and plasma/urine catecholamine levels. Caffeine intake has been associated with a range of reversible and transient physiological effects broadly and cardiovascular effects specifically. This report attempts to understand where the delineations exist in caffeine intake and corresponding cardiovascular effects among various subpopulations. The available literature suggests that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect. The point at which caffeine intake may cause harm to the cardiovascular system is not readily identifiable in part because data on the effects of daily intakes greater than 600 mg is limited. However, the evidence considered within this review suggests that typical moderate caffeine intake is not associated with increased risks of total cardiovascular disease; arrhythmia; heart failure; blood pressure changes among regular coffee drinkers; or hypertension in baseline populations.
Topics: Caffeine; Cardiovascular Diseases; Cardiovascular System; Central Nervous System Stimulants; Coffee; Hemodynamics; Humans
PubMed: 28756014
DOI: 10.1016/j.yrtph.2017.07.025 -
Neuroscience and Biobehavioral Reviews Dec 2016Caffeine 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... (Review)
Review
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.
Topics: Caffeine; Central Nervous System Stimulants; Cognition; Humans; Reaction Time; Sleep; Wakefulness
PubMed: 27612937
DOI: 10.1016/j.neubiorev.2016.09.001 -
Nutrition Research (New York, N.Y.) Aug 2020Caffeine, a xanthine alkaloid compound, is consumed widely and daily by humans, as it is present in several regular beverages such as tea, coffee, soda beverages, and... (Review)
Review
Caffeine, a xanthine alkaloid compound, is consumed widely and daily by humans, as it is present in several regular beverages such as tea, coffee, soda beverages, and some drugs. Its consumption triggers arousal and alertness, improves mood, and causes the release of catecholamines, which induce beneficial effects on human behavior. Nonetheless, caffeine has been related to other beneficial effects such as antioxidant and anti-inflammatory actions that are extremely important to human health, altering the cellular redox and inflammatory status in a dose-dependent manner. Caffeine intake has also shown ergogenic effects, which are attributed to different factors, such as enhanced substrate utilization, fatigue delay, and alertness. As such, caffeine has been consumed by athletes from different sports modalities, with positive and negative effects declared. Although peripheral tissues such as the heart, skeletal muscle, and adipocytes are also impacted, there is a deficit of recognized mechanisms in systemic metabolism when compared to caffeine action in the central nervous system. This review summarizes the most relevant classical and current literature available regarding the use of caffeine in different metabolic situations, such as oxidative and inflammatory status, as well as anaerobic and aerobic physical exercises. Here, we identified the non-central nervous system caffeine mechanisms modulation, as most are still unknown or controversial, highlighting its influence in the peripheral system and its essential and crucial impacts on the human's organism adaptation.
Topics: Athletic Performance; Caffeine; Central Nervous System Stimulants; Exercise; Humans; Inflammation; Metabolism; Oxidation-Reduction; Oxidative Stress
PubMed: 32589582
DOI: 10.1016/j.nutres.2020.05.005 -
Skin Pharmacology and Physiology 2020Caffeine, particularly after ingestion, is well known to exert various pharmacological effects. A growing body of evidence implicates the ingestion of caffeine with... (Review)
Review
Caffeine, particularly after ingestion, is well known to exert various pharmacological effects. A growing body of evidence implicates the ingestion of caffeine with beneficial effects on several diseases. The easy penetration of caffeine across the skin barrier and into human skin makes caffeine an ideal compound for topical application. Hair loss is known to negatively affect the quality of life and predispose to depression and anxiety. Androgenetic alopecia (AGA) is the most common type of hair loss in both men and women. To date, only few approved drug-based treatments for AGA exist, and these are inevitably associated with side effects. Therefore, the development of topical treatments based on well-tolerated natural ingredients such as caffeine to alleviate hair loss may provide a much-needed alternative to drug-based approaches.
Topics: Alopecia; Caffeine; Central Nervous System Stimulants; Humans
PubMed: 32599587
DOI: 10.1159/000508228 -
International Journal of Environmental... Nov 2021The prevalence of ED consumption has increased over the past 10-15 years. Studies describing the effects of caffeine and caffeinated beverages show confusing results, so... (Review)
Review
The prevalence of ED consumption has increased over the past 10-15 years. Studies describing the effects of caffeine and caffeinated beverages show confusing results, so it seems important to regularly summarize the available facts, and in more detail. By a thorough analysis of more than 156 scientific papers, the authors describe the molecular background of absorption, as well as the positive and negative effects of different dosages of caffeine, just like its effects in physical activity and performance. ED and EDwA consumption is a regular habit of not only adults, but nowadays even of children and adolescents. There are no safe dosages described of caffeine or ED consumption for children. There are no positive short- or long-term effects of these compounds/products concerning developing brain functions, psycho-motor functions, or social development. Instead, there are many unpleasant side effects, and symptoms of regular or higher-dose ED consumption, especially at younger ages. This mini review describes many details of these unpleasant side effects, their severity, and motivations for consuming these compounds/products. In a quantitative research in Hungary (10-26 years, mean age: 15.6 ± 3.8 y, 1459 subjects, randomly chosen population), a survey based on a questionnaire asking people about their ED consumption habits was conducted. According to the data, 81.8% of the participants consumed EDs at least once, and 63.3% tried several products of the kind. A positive correlation was found between age and consumption ( < 0.001). The results show that a high proportion of this group often consumed EDwA, in many cases leading to harmful side-effects of caffeine overdose. In a sample of Hungarian high school and college students (17-26 years), ED consumption matched the international data, and only 19.7% of respondents did not use EDs at all (had never tasted an ED in their life).
Topics: Adolescent; Adult; Beverages; Caffeine; Child; Energy Drinks; Humans; Motivation; Students; Surveys and Questionnaires; Young Adult
PubMed: 34886115
DOI: 10.3390/ijerph182312389 -
Nutrients Nov 2018Coffee, tea, caffeinated soda, and energy drinks are important sources of caffeine in the diet but each present with other unique nutritional properties. We review how... (Review)
Review
Coffee, tea, caffeinated soda, and energy drinks are important sources of caffeine in the diet but each present with other unique nutritional properties. We review how our increased knowledge and concern with regard to caffeine in the diet and its impact on human health has been translated into food-based dietary guidelines (FBDG). Using the Food and Agriculture Organization list of 90 countries with FBDG as a starting point, we found reference to caffeine or caffeine-containing beverages (CCB) in 81 FBDG and CCB consumption data (volume sales) for 56 of these countries. Tea and soda are the leading CCB sold in African and Asian/Pacific countries while coffee and soda are preferred in Europe, North America, Latin America, and the Caribbean. Key themes observed across FBDG include (i) caffeine-intake upper limits to avoid risks, (ii) CCB as replacements for plain water, (iii) CCB as added-sugar sources, and (iv) health benefits of CCB consumption. In summary, FBDG provide an unfavorable view of CCB by noting their potential adverse/unknown effects on special populations and their high sugar content, as well as their diuretic, psycho-stimulating, and nutrient inhibitory properties. Few FBDG balanced these messages with recent data supporting potential benefits of specific beverage types.
Topics: Asia; Beverages; Caffeine; Carbonated Beverages; Coffee; Commerce; Diet; Energy Drinks; Europe; Humans; North America; Nutrition Policy; Tea
PubMed: 30445721
DOI: 10.3390/nu10111772 -
Trends in Endocrinology and Metabolism:... Mar 2020Epidemiological studies have revealed that caffeine consumption during pregnancy is associated with adverse gestational outcomes, yet the underlying mechanisms remain... (Review)
Review
Epidemiological studies have revealed that caffeine consumption during pregnancy is associated with adverse gestational outcomes, yet the underlying mechanisms remain obscure. Recent animal studies with physiologically relevant dosages have begun to dissect adverse effects of caffeine during pregnancy with respect to oviduct contractility, embryo development, uterine receptivity, and placentation that jointly contribute to pregnancy complications. Interestingly, caffeine's effects are highly variable between individual animals under well-controlled experimental settings, suggesting the possibility of epigenetic regulation of these phenotypes, in addition to genetic variants. Moreover, caffeine exposure during sensitive windows of pregnancy may induce epigenetic changes in the developing fetus or even the germ cells to cause adult-onset diseases in subsequent generations. We discuss these research frontiers in light of emerging data.
Topics: Animals; Caffeine; Epigenesis, Genetic; Female; Humans; Maternal Nutritional Physiological Phenomena; Pregnancy; Prenatal Exposure Delayed Effects
PubMed: 31818639
DOI: 10.1016/j.tem.2019.11.004