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caffeine and performance

Rhonda Orr, Matthew Grassmayr, Rona Macniven, Anne Grunseit, Mark Halaki, Adrian Bauman
BACKGROUND: This study investigated athlete knowledge of the World Anti-doping Agency (WADA) Prohibited Substances List and the effects of four well-known performance enhancing substances (PES). METHODS: A sample of 1925 elite and sub-elite athletes (mean age 20.6 years) completed a questionnaire about the banned status of 30 substances/methods and their knowledge of the effects of amphetamines, anabolic steroids, growth hormone and erythropoietin. RESULTS: Athletes showed limited understanding of the WADA Prohibited Substances List, scoring 32...
March 15, 2018: International Journal on Drug Policy
Xiao-Dong Zhang, Zana A Coulibaly, Wei Chun Chen, Hannah A Ledford, Jeong Han Lee, Padmini Sirish, Gu Dai, Zhong Jian, Frank Chuang, Ingrid Brust-Mascher, Ebenezer N Yamoah, Ye Chen-Izu, Leighton T Izu, Nipavan Chiamvimonvat
Small-conductance Ca2+ -activated K+ (SK) channels regulate the excitability of cardiomyocytes by integrating intracellular Ca2+ and membrane potentials on a beat-to-beat basis. The inextricable interplay between activation of SK channels and Ca2+ dynamics suggests the pathology of one begets another. Yet, the exact mechanistic underpinning for the activation of cardiac SK channels remains unaddressed. Here, we investigated the intracellular Ca2+ microdomains necessary for SK channel activation. SK currents coupled with Ca2+ influx via L-type Ca2+ channels (LTCCs) continued to be elicited after application of caffeine, ryanodine or thapsigargin to deplete SR Ca2+ store, suggesting that LTCCs provide the immediate Ca2+ microdomain for the activation of SK channels in cardiomyocytes...
March 16, 2018: Scientific Reports
Sandrina Lampis, Maura Carboni, Daniela Steri, Sergio Murgia, Maura Monduzzi
Lipid based formulations, endowed of long term stability as a result of the formation of lamellar liquid crystals, were prepared using the natural lipids lecithin and glycerol trioleate in water, and characterized using optical microscopy, SAXRD and NMR. The formulations, designed as possible carriers for lysozyme and caffeine, were evaluated for structural features and stability after the loading of the guest molecules. Release experiments were performed at 37 °C using the PBS medium. No burst release was observed either for lysozyme or caffeine...
March 2, 2018: Colloids and Surfaces. B, Biointerfaces
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
Tom M McLellan, Lyndon A Riviere, Kelly W Williams, Dennis McGurk, Harris R Lieberman
OBJECTIVES: Combat deployments are characterized by high operational demands with limited opportunities for sleep leading to fatigue and degraded cognitive and operational performance. Caffeine in moderate doses is recognized as an effective intervention for physical and cognitive decrements associated with sleep loss. METHODS: This report is based on data collected by two separate, independently conducted surveys administered in Afghanistan in 2011-2012. It assessed caffeine use and sleep disruption among U...
March 11, 2018: Nutritional Neuroscience
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
S Parvez, R R Gerona, C Proctor, M Friesen, J L Ashby, J L Reiter, Z Lui, P D Winchester
BACKGROUND: Glyphosate (GLY) is the most heavily used herbicide worldwide but the extent of exposure in human pregnancy remains unknown. Its residues are found in the environment, major crops, and food items that humans, including pregnant women, consume daily. Since GLY exposure in pregnancy may also increase fetal exposure risk, we designed a birth-cohort study to determine exposure frequency, potential exposure pathways, and associations with fetal growth indicators and pregnancy length...
March 9, 2018: Environmental Health: a Global Access Science Source
Wolfgang Schwack, Elodie Pellissier, Gertrud Morlock
Food authenticity and food safety are of high importance to organizations as well as to the food industry to ensure an accurate labeling of food products. Respective analytical methods should provide a fast screening and a reliable cost-efficient quantitation. HPTLC was pointed out as key analytical technique in this field. A new HPTLC method applying caffeine-impregnated silica gel plates was developed for eight most frequently found fat-soluble azo dyes unauthorizedly added to spices, spice mixtures, pastes, sauces, and palm oils...
March 7, 2018: Analytical and Bioanalytical Chemistry
Carolina Bussoletti, Maria V Tolaini, Leonardo Celleno
BACKGROUND: Androgenetic alopecia (AGA) is the most common type of hair loss in both males as well as females, occurring in up to 57% of women by the age of 80 years. Androgenetic alopecia is associated with a high psychological burden and often results in substantially reduced quality of life, poor body image and low self-esteem, particularly in women. Caffeine-based products have shown promise, both in vitro and in vivo, as potential treatments for AGA. This study was performed to determine the efficacy of a phyto-caffeine- containing shampoo used over a 6-month period in female subjects with AGA...
March 6, 2018: Giornale Italiano di Dermatologia e Venereologia: Organo Ufficiale, Società Italiana di Dermatologia e Sifilografia
Hue T M Tran, Thiruvarangan Ramaraj, Agnelo Furtado, L Slade Lee, Robert J Henry
Arabica coffee (Coffea arabica) has a small gene pool limiting genetic improvement. Selection for caffeine content within this gene pool would be assisted by identification of the genes controlling this important trait. Sequencing of DNA bulks from 18 genotypes with extreme high or low caffeine content from a population of 232 genotypes was used to identify linked polymorphisms. To obtain a reference genome a whole genome assembly of arabica coffee (variety K7) was achieved by sequencing using short read (Illumina) and long read (PacBio) technology...
March 6, 2018: Plant Biotechnology Journal
Nanci Guest, Paul Corey, Jason Vescovi, Ahmed El-Sohemy
PURPOSE: Many studies have examined the effect of caffeine on exercise performance, but findings have not always been consistent. The objective of this study was to determine whether variation in the CYP1A2 gene, which affects caffeine metabolism, modifies the ergogenic effects of caffeine in a 10-km cycling time trial. METHODS: Competitive male athletes (n=101; age: 25 ± 4 years) completed the time trial under three conditions: 0, 2 or 4 mg of caffeine per kg body mass, using a split-plot randomized, double-blinded, placebo-controlled design...
March 5, 2018: Medicine and Science in Sports and Exercise
Sissel Kramer Aagaard, Agnete Larsen, Mette Findal Andreasen, Iana Lesnikova, Rasmus Telving, Anna Louise Vestergaard, Niels Tørring, Niels Uldbjerg, Pinar Bor
OBJECTIVE: The aim of this study was to investigate the prevalence of xenobiotic substances, such as caffeine, nicotine and illicit drugs (eg, cannabis and cocaine), in blood samples from first-trimester Danish pregnant women unaware of the screening. DESIGN: A cross - sectional study examined 436 anonymised residual blood samples obtained during 2014 as part of the nationwide prenatal first-trimester screening programme. The samples were analysed by ultra performance liquid chromatography with high-resolution time-of-flight mass spectrometry...
March 3, 2018: BMJ Open
I A Vasiliadou, R Molina, F Martinez, J A Melero, P M Stathopoulou, G Tsiamis
Micropollutants of emerging concern such as pharmaceuticals can significantly affect the performance of secondary biological processes in wastewater treatment plants. The present study is aimed to evaluate the toxicity and inhibition of three pharmaceutical compounds (caffeine, sulfamethoxazole and carbamazepine) on two cultures of microbial consortia enriched from wastewater aerobic activated sludge. One of them was acclimated to pharmaceuticals and the other was non-acclimated as control bioassay. The toxic and inhibitory effects on these cultures were assessed by respirometric tests through the oxygen uptake rate as an indicator of their capacity to degrade a readily available carbon source...
February 26, 2018: Science of the Total Environment
Xueting Feng, Wei Zhang, Tenghe Zhang, Shun Yao
BACKGROUND: Magnetic separation has become a mature industrial technique in many fields, and its application in food and agricultural fields is expected for further extension. Furthermore, the application of magnetic ionic liquids in the preparation of bioactive products is little. In this study, 0.8 mol L-1 C3 MIMFeCl4 in its aqueous solution was found ideal for the extraction of active constituents from tea leaves. After extraction, polyphenols, caffeine and ionic liquid were also satisfactorily separated from the crude extract by various easy operations...
February 27, 2018: Journal of the Science of Food and Agriculture
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
Michael S Green, Tyler D Martin, Benjamin T Corona
Caffeine use is common among athletes seeking to capitalize on its potential ergogenic effects. Limited research has examined caffeine's effects when utilized following activities that resulted in exercise-induced muscle damage (EIMD). This study examined the effect of caffeine supplementation on uninjured and injured muscle. Eight male and female (N = 16) physically active individuals participated (age: 24.3 ± 4.3 y; height: 173.0 ± 7.0 cm, mass: 75.2 ± 11.5 kg; body fat: 18.2 ± 15.9 %). One leg was assessed under uninjured and injured (100 eccentric quadriceps contractions) conditions following caffeine supplementation (6 mg/kg), with the other leg assessed under both conditions following placebo supplementation...
February 22, 2018: Journal of Strength and Conditioning Research
Salma M Eraky, Mohamed El-Mesery, Amro El-Karef, Laila A Eissa, Amal M El-Gayar
AIMS: Lysophosphatidic acid is a lipid mediator that is supposed to be implicated in hepatic fibrosis. Silymarin and caffeine are natural compounds known for their anti-inflammatory and antioxidant effects. Our study aimed to explore the effect of silymarin, caffeine, and their combination on lysophosphatidic acid receptor 1 (LPAR1) pathway in thioacetamide (TAA)-induced hepatic fibrosis. MAIN METHODS: Hepatic fibrosis was induced in male Sprague-Dawley rats by intraperitoneal injection of 200 mg/kg of TAA twice a week for 8 weeks...
February 21, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
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
Peter Peeling, Martyn J Binnie, Paul S R Goods, Marc Sim, Louise M Burke
A strong foundation in physical conditioning and sport-specific experience, in addition to a bespoke and periodized training and nutrition program, are essential for athlete development. Once these underpinning factors are accounted for, and the athlete reaches a training maturity and competition level where marginal gains determine success, a role may exist for the use of evidence-based performance supplements. However, it is important that any decisions surrounding performance supplements are made in consideration of robust information that suggests the use of a product is safe, legal, and effective...
February 21, 2018: International Journal of Sport Nutrition and Exercise Metabolism
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