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Caffeine ingestion

Ronald J Maughan, Louise M Burke, Jiri Dvorak, D Enette Larson-Meyer, Peter Peeling, Stuart M Phillips, Eric S Rawson, Neil P Walsh, Ina Garthe, Hans Geyer, Romain Meeusen, Lucas J C van Loon, Susan M Shirreffs, Lawrence L Spriet, Mark Stuart, Alan Vernec, Kevin Currell, Vidya M Ali, Richard Gm Budgett, Arne Ljungqvist, Margo Mountjoy, Yannis P Pitsiladis, Torbjørn Soligard, Uğur Erdener, Lars Engebretsen
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition programme. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including (1) the management of micronutrient deficiencies, (2) supply of convenient forms of energy and macronutrients, and (3) provision of direct benefits to performance or (4) indirect benefits such as supporting intense training regimens...
March 14, 2018: British Journal of Sports Medicine
Rahman Rahimi
AIM: The purpose of this study was to examine the effect of CYP1A2 -163C>A polymorphism on the ergogenic effects of caffeine supplementation during a resistance exercise (RE) session. METHODS: In a randomized, double-blind, placebo (PL)-controlled, crossover study, 30 resistance-trained men took part in two RE sessions (three sets to failure at 85% of one repetition maximum, 2-min rest between sets), including bench press (BP), leg press (LP), seated cable row, and shoulder press (SP) following caffeine (CAF) (6 mg kg-1 ) or PL (6 mg kg-1 of maltodextrin) ingestion 1 h prior to the trial...
March 12, 2018: Irish Journal of Medical Science
Jozo Grgic, Eric T Trexler, Bruno Lazinica, Zeljko Pedisic
Background: Caffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power. Methods: A search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump...
2018: Journal of the International Society of Sports Nutrition
Yoshito Kamijo, Michiko Takai, Yuji Fujita, Kiyotaka Usui
Objective We conducted a retrospective study on the epidemiological and clinical features of patients with acute caffeine poisoning in Japan. Methods Letters requesting participation were sent to 264 emergency departments of hospitals, and questionnaires were mailed to those that agreed to participate. Patients Participants were patients transported to emergency departments of hospitals between April 2011 and March 2016 after consuming large or massive amounts of caffeinated supplements and/or energy drinks (caffeine dose ≥1...
March 9, 2018: Internal Medicine
Rogerio Nogueira Soares, Augusto Schneider, Sandra Costa Valle, Paulo Cavalheiro Schenkel
This study aimed to investigate whether the influence of CYP1A2 genotype in the blood pressure (BP) response to caffeine ingestion was affected by physical activity status and habitual caffeine consumption. Thirty-seven participants (19-50 years old) took place in the study and were categorized according to i) genotype: CYP1A2 (AA) "fast metabolizer", and CYP1A2 (AC) "slow metabolizer"; ii) physical activity level: sedentary (S) and physically active (A); and iii) caffeine consumption level: non-habitual caffeine consumer (NC) and habitual heavy caffeine consumer (C)...
March 6, 2018: Vascular Pharmacology
Astrid Nehlig
Most individuals adjust their caffeine intake according to the objective and subjective effects induced by the methylxanthine. However, to reach the desired effects, the quantity of caffeine consumed varies largely among individuals. It has been known for decades that the metabolism, clearance, and pharmacokinetics of caffeine is affected by many factors such as age, sex and hormones, liver disease, obesity, smoking, and diet. Caffeine also interacts with many medications. All these factors will be reviewed in the present document and discussed in light of the most recent data concerning the genetic variability affecting caffeine levels and effects at the pharmacokinetic and pharmacodynamic levels that both critically drive the level of caffeine consumption...
April 2018: Pharmacological Reviews
Joanna L Bowtell, Magni Mohr, Jonathan Fulford, Sarah R Jackman, Georgios Ermidis, Peter Krustrup, Katya N Mileva
Background: Caffeine has been shown to enhance exercise performance and capacity. The mechanisms remain unclear but are suggested to relate to adenosine receptor antagonism, resulting in increased central motor drive, reduced perception of effort, and altered peripheral processes such as enhanced calcium handling and extracellular potassium regulation. Our aims were to investigate how caffeine (i) affects knee extensor PCr kinetics and pH during repeated sets of single-leg knee extensor exercise to task failure and (ii) modulates the interplay between central and peripheral neural processes...
2018: Frontiers in Nutrition
Leandro Camati Felippe, Guilherme Assuncao Ferreira, Sara Kely Learsi, Daniel Boari, Rômulo Bertuzzi, Adriano Eduardo Lima-Silva
The link between total work performed above critical power (CP) and peripheral muscle fatigue during self-paced exercise is unknown. We investigated the influence of caffeine on the total work done above CP during a 4-km cycling time trial (TT), and the subsequent consequence on the development of central and peripheral fatigue. Nine cyclists performed three constant-load exercise trials to determine CP and two 4-km TT ~75 min after oral caffeine (5 mg·kg-1 ) or cellulose (placebo) ingestion. Neuromuscular functions were assessed before and 50 min after supplementation, and 1 min after TT...
February 22, 2018: Journal of Applied Physiology
Johanna Oskarsson, Kerry McGawley
BACKGROUND: Dietary supplements such as caffeine and beetroot juice are used by athletes in an attempt to optimize performance and therefore gain an advantage in competition. AIM: To investigate the individual and combined effects of caffeine and beetroot-juice supplementation during submaximal and maximal treadmill running. METHODS: Seven males (VO<sub>2max</sub>: 59.0 ± 2.9 mL/kg/min) and two females (VO<sub>2max</sub>: 53...
February 14, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Ian C Dunican, Charles C Higgins, Maddison J Jones, Michael W Clarke, Kevin Murray, Brian Dawson, John A Caldwell, Shona L Halson, Peter R Eastwood
OBJECTIVE: To examine the relationship between regular game-related caffeine consumption on sleep after an evening Super Rugby game. METHODS: Twenty elite rugby union players wore a wrist-activity monitor to measure sleep for three days before, three days after and on the night of an evening Super Rugby game (19:00-21:00). Players ingested caffeine as they would normally (i.e. before and sometimes during a game) and saliva samples were collected before (17:00) and after (21:30) the game for caffeine concentration...
February 12, 2018: European Journal of Sport Science
Da Chang, Donghui Song, Jian Zhang, Yuanqi Shang, Qiu Ge, Ze Wang
Entropy is an important trait of brain function and high entropy indicates high information processing capacity. We recently demonstrated that brain entropy (BEN) is stable across time and differs between controls and patients with various brain disorders. The purpose of this study was to examine whether BEN is sensitive to pharmaceutical modulations with caffeine. Both cerebral blood flow (CBF) and resting fMRI were collected from sixty caffeine-naïve healthy subjects before and after taking a 200 mg caffeine pill...
February 9, 2018: Scientific Reports
Olivia E Knowles, Eric J Drinkwater, Charles S Urwin, Séverine Lamon, Brad Aisbett
OBJECTIVES: Inadequate sleep (e.g., an insufficient duration of sleep per night) can reduce physical performance and has been linked to adverse metabolic health outcomes. Resistance exercise is an effective means to maintain and improve physical capacity and metabolic health, however, the outcomes for populations who may perform resistance exercise during periods of inadequate sleep are unknown. The primary aim of this systematic review was to evaluate the effect of sleep deprivation (i...
February 2, 2018: Journal of Science and Medicine in Sport
Sunita Potgieter, Hattie H Wright, Carine Smith
The ergogenic effect of caffeine on endurance exercise is commonly accepted. We aimed to elucidate realistically the effect of caffeine on triathlon event performance using a field study design, while allowing investigation into potential mechanisms at play. A double-blind, randomized, crossover, field trial was conducted. Twenty-six triathletes (14 males, 12 females) participated (age: 37.8±10.6 years, habitual caffeine intake: 413±505 mg/day, percentage body fat: 14.5±7.2%, training/week: 12.8±4.5 hours)...
January 18, 2018: International Journal of Sport Nutrition and Exercise Metabolism
Chelsea J Hahn, Andrew R Jagim, Clayton L Camic, Matthew J Andre
Studies show mixed results for the effects of caffeine on performance, warranting further investigation. The purpose of this study was to examine the acute effects of a caffeine-containing supplement on anaerobic power and subjective measurements of fatigue during resisted sprinting on males. Fourteen recreationally-active males [N=14; (mean±SD), age: 21.0±0.7 yrs., height: 178.5±5.1 cm, weight: 77.3±9.6 kg, percent body fat: 12.6±4.8%] participated in a double-blind, placebo controlled, within-subjects crossover design study...
January 4, 2018: Journal of Strength and Conditioning Research
Natalie W Young, Kenneth D Royal, Gigi S Davidson
Background: Consumer expenditures on their family pets are rapidly increasing, part of which can be attributed to prescription and OTC medications. In turn, community pharmacies are seeking and receiving an increased number of prescriptions for animals. Community pharmacists' ability to safely care for animal patients is relatively unexplored. Human medications, their normal dosing and even medication excipients could be lethal in some animal patients. Objective: The overarching objective of this study was to assess pharmacists' baseline knowledge of potential pet poisons...
October 2017: Pharmacy Practice
Christopher W N Saville, H M de Morree, Neil M Dundon, S M Marcora, C Klein
BACKGROUND: Caffeine has a well-established effect on reaction times (RTs) but the neurocognitive mechanisms underlying this are unclear. METHODS: In the present study, 15 female participants performed an oddball task after ingesting caffeine or a placebo, and electroencephalographic data were obtained. Single-trial P3b latencies locked to the stimulus and to the response were extracted and mediation models were fitted to the data to test whether caffeine's effect on RTs was mediated by its effect on either type of P3b latencies...
December 23, 2017: Psychopharmacology
Simon Devenney, Shane Mangan, Marcus Shortall, Kieran Collins
The current study aims to identify if mouth rinsing with a 6% carbohydrate solution (CMR) and mouth rinsing and ingestion of caffeine (CMR+CAFF) can affect exercise performance during steady state (SS) running and high intensity intervals (HIT) in comparison to a 0% control solution (PLA), when in a fed state. Eight recreationally trained males completed three trials (CMR, CMR + CAFF, and PLA) of 45-min SS run and a HIT protocol (90% peak treadmill velocity) until fatigue in a double blinded, repeated measures study...
December 20, 2017: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Christine Perdan Curran, Cecile A Marczinski
Energy drinks are emerging as a major component of the beverage market with sales projected to top $60 billion globally in the next five years. Energy drinks contain a variety of ingredients, but many of the top-selling brands include high doses of caffeine and the amino acid taurine. Energy drink consumption by children has raised concerns, due to potential caffeine toxicity. An additional risk has been noted among college-aged consumers of energy drinks who appear at higher risk of over-consumption of alcohol when the two drinks are consumed together...
December 1, 2017: Birth defects research
Jeroen Van Cutsem, Kevin De Pauw, Samuele Marcora, Romain Meeusen, Bart Roelands
INTRODUCTION: Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity that has negative implications on many aspects in daily life. Caffeine and carbohydrate ingestion have been shown to be able to reduce these negative effects of mental fatigue. Intake of these substances might however be less desirable in some situations (e.g., restricted caloric intake, Ramadan). Rinsing caffeine or glucose within the mouth has already been shown to improve exercise performance...
December 15, 2017: Psychopharmacology
Grant M Tinsley, Stacie Urbina, Jacy Mullins, Jordan Outlaw, Sara Hayward, Matt Stone, Cliffa Foster, Colin Wilborn, Lem Taylor
Dietary supplementation is commonly employed by individuals seeking to improve body composition and exercise performance. The purpose of the present study was to examine the safety and effectiveness of a commercially available dietary supplement designed to promote thermogenesis and fat loss. In a randomized double-blind trial, participants were assigned to consume placebo or a multi-ingredient supplement containing caffeine, green tea extract, l-carnitine, evodiamine and other ingredients that purportedly enhance thermogenesis...
December 2017: Journal of Sports Science & Medicine
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