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Ana Andrade, Catarina Sousa, Mónica Pedro, Martinho Fernandes
Caffeine (1,3,7-trimethylxanthine) is a natural product commonly presented in food's composition, beverages and medicinal products. Generally, it is thought to be safe under normal dosage, yet it can be fatal in case of severe intoxication. We report a case of a healthy 32-year-old woman who went to the local emergency department (ED) 30 min after ingesting, accidentally, 5000 mg of anhydrous caffeine for a preworkout supplement. At the ED, she presented an episode of presyncope followed by agitation. ECG showed polymorphic broad complex QRS tachycardia and arterial blood gas revealed metabolic acidaemia with severe hypokalemia...
June 8, 2018: BMJ Case Reports
Kevin F Elwood, Robert W Wong
PURPOSE: To describe a case of transient, partial, central retinal artery occlusion with paracentral acute middle maculopathy optical coherence tomography presentation in a young healthy patient after ingestion of the synephrine-containing supplement, Havok. METHODS: Retrospective case report with fundus photography, fluorescein angiography, and optical coherence tomography. RESULTS: A 20-year-old man presented with severe acute vision loss in the right eye...
March 8, 2018: Retinal Cases & Brief Reports
Adam Přibylka, Martin Švidrnoch, Juraj Ševčík, Vítězslav Maier
The CE method employing an indirect UV detection for the enantioseparation of 1,3-dimethylamylamine (DMAA), widely used in various preworkout and dietary supplements labeled as a constituent of geranium extract has been developed. The dual-selector system consisting of negatively charged sulfated α-CD (1.1% w/v) and sulfated β-CD (0.2% w/v) in 5 mM phosphate/Tris buffer (pH 3.0) containing the addition of 10 mM benzyltriethylammonium chloride (BTEAC) as the chromophoric additive was used for the enantiomeric separation of DMAA stereoisomers with the LODs in the range of 7...
December 2015: Electrophoresis
Bharathi Avula, Troy J Smillie, Yan-Hong Wang, Jerry Zweigenbaum, Mahmoud A ElSohly, Ikhlas A Khan
The central nervous system stimulant 1,3-dimethylamylamine (DMAA) has been found in preworkout products and dietary supplements. A fast direct analysis in real time-quadrupole time of flight-MS method was used for identification of DMAA in dietary supplements and to determine if this compound is present in geranium (Pelargonium graveolens) plants or oil. This method involved the use of [M+H]+ ions in the positive mode based on the exact mass of DMAA. The results of this investigation showed that DMAA was not detected from authentic samples of P...
May 2015: Journal of AOAC International
Kristina L Kendall, Jordan R Moon, Ciaran M Fairman, Brandon D Spradley, Chih-Yin Tai, Paul H Falcone, Laura R Carson, Matt M Mosman, Jordan M Joy, Michael P Kim, Eric R Serrano, Enrico N Esposito
The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days...
May 2014: Nutrition Research
William J Kraemer, Brittny M Boyd, David R Hooper, Maren S Fragala, Disa L Hatfield, Courtenay Dunn-Lewis, Brett A Comstock, Tunde K Szivak, Shawn D Flanagan, David P Looney, Robert U Newton, Jakob L Vingren, Keijo Häkkinen, Mark T White, Jeff S Volek, Carl M Maresh
The optimal time of day for training has become an important question for many strength and conditioning specialists, and this study was designed to add some insights into this complex question. The primary purpose of this investigation was to examine physical performance within the temporal context of the relationship between physical performance, epinephrine, and melatonin concentrations in the early morning (0530 hours) and late (1500 hours) afternoon in elite collegiate male track and field athletes (jumpers and sprinters)...
September 2014: Journal of Strength and Conditioning Research
Anne E Eudy, Lindsay L Gordon, Brandon C Hockaday, Daniel A Lee, Vivianne Lee, Daniel Luu, Carlos A Martinez, Peter J Ambrose
PURPOSE: Published evidence on common ingredients of "energy drinks" and other dietary supplements widely used by consumers in hopes of enhancing athletic performance is reviewed. SUMMARY: Preworkout products- unregulated dietary supplements- typically contain "proprietary blends" of multiple ingredients, including caffeine, dimethylamylamine, creatine, arginine, β-alanine, taurine, and phosphates. While some dietary supplement labels instruct consumers to seek the advice of a health care professional before using the products, the labels usually do not disclose all ingredients or their precise amounts, and evidence to support the purported performance-enhancing benefits is generally lacking...
April 1, 2013: American Journal of Health-system Pharmacy: AJHP
Blair T Crewther, Christian J Cook, Chris M Gaviglio, Liam P Kilduff, Scott Drawer
The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM < 1.9 × body weight, n = 5). The good squatters were stronger than the average squatters (p < 0.05). Each subject was assessed for squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period...
January 2012: Journal of Strength and Conditioning Research
Marco Machado, Alexander J Koch, Jeffrey M Willardson, Frederico C dos Santos, Victor M Curty, Lucas N Pereira
PURPOSE: The purpose of this study was to evaluate the effects of caffeine ingestion before a resistance exercise session on markers of muscle damage (CK, LDH, ALT, AST) and leukocyte levels. METHODS: Fifteen soccer athletes completed two resistance exercise sessions that differed only in the ingestion of caffeine or a placebo preworkout. RESULTS: CK concentration increased significantly following the caffeine session (415.8+/-62.8 to 542...
March 2010: International Journal of Sports Physiology and Performance
Christopher M Lockwood, Jordan R Moon, Abbie E Smith, Sarah E Tobkin, Kristina L Kendall, Jennifer L Graef, Joel T Cramer, Jeffrey R Stout
Energy drink use has grown despite limited research to support efficacy or safety and amid concerns when combined with exercise. The purpose of this study was to assess the effects of 10 weeks of once-daily energy drink consumption or energy drink consumption with exercise on measures of body composition, cardiorespiratory fitness, strength, mood, and safety in previously sedentary males. Thirty-eight males were randomly assigned to energy drink + exercise (EX-A), energy drink (NEX-A), placebo + exercise (EX-B), or placebo (NEX-B)...
August 2010: Journal of Strength and Conditioning Research
Matthew R Rhea, Derek Bunker, Pedro J Marín, Kregg Lunt
Attempts to reduce or eliminate delayed-onset of muscle soreness are important as this condition is painful and debilitating. The purpose of this study was to examine the effectiveness of whole-body vibration (WBV) massage and stretching exercises at reducing perceived pain among untrained men. Sixteen adult men (age, 36.6 +/- 2.1 yr) volunteered to perform a strenuous exercise session consisting of resistance training and repeated sprints. Subjects were randomly assigned to 1 of 2 recovery groups: a group performing WBV stretching sessions or a stretching group performing static stretching without vibration...
September 2009: Journal of Strength and Conditioning Research
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