BackgroundA number of nutritional strategies have been developed to optimize nutrient delivery prior to exercise. As a result, a number of pre-workout supplements have been developed to increase energy availability, promote vasodilation, and/ or positively affect exercise capacity. The purpose of this study was to examine the acute effects of ingesting a preworkout dietary supplement with and without synephrine on energy metabolism and cardiovascular hemodynamics. MethodsIn a double-blind, crossover, randomized and placebocontrolled manner; 25 apparently healthy and recreationally active men and women (21.76±3.00 yr, 15.24±5.26% fat, 25.09±3.03 kg/m2) volunteered to participate in this study and had resting blood pressure (BP), heart rate (HR), 12-lead electrocardiographs (ECG), and resting energy expenditure (REE) measured for 10 minutes. Participants then ingested in a randomized and counterbalanced manner a dextrose flavored placebo (P); a preworkout supplement (PWS) containing 3.0 g beta alanine, 2 g creatine nitrate, 2 g arginine AKG, 300 mg of N-acetyl tyrosine, 270 mg caffeine, 15 mg of Mucuna pruriens; or, the PWS with 20 mg of synephrine (PWS+S). Metabolic changes were measured continuously while BP, HR, and ECG's were obtained every 10 minutes during the REE test. Participants repeated the experiment after a one week washout period with the alternate supplements in a randomized and counterbalanced manner. Data were analyzed by repeated measure MANOVA and are presented as means ± SD or SEM from baseline. Consent to publish the results was obtained from all participants. ResultsMANOVA analysis revealed a significant overall Wilks' Lambda time (p<0.001) and time x group interactions (p<0.001) for oxygen uptake (VO2), carbon dioxide production (VCO2), minute ventilation (Ve), respiratory exchange ratio (RER), and REE values. MANOVA Greenhouse-Geisser univariate analysis revealed significant interactions among groups in VCO2 (p=0.003) and RER (p<0.001) with a trend toward significance in REE (p=0.098). Delta analysis revealed significant differences among groups in mean change in VO2 (P: 3.8±5.2; PWS: 15.4±5.2; PWS+S: 23.5±5.2 ml/min; p=0.03), VCO2 (P: 12.5±5.1; PWS: 31.8±5.1; PWS+S: 37.7±5.1 ml/min; p=0.002), RER (P: 0.033±0.009; PWS: 071±0.009; PWS +S: 0.071±0.009; p=0.005), and REE (P: 0.034±0.025; PWS: 0.095±0.025; PWS+S: 0.132±0.025 kcal/min; p=0.02) with significant differences observed among the P group and both supplemented groups. PWS-S ingestion promoted a more prominent increase in VO2, VCO2, and REE during the initial 5-10 minutes after ingestion with differences minimizing thereafter. Area under the curve (AUC) analysis of changes from baseline revealed that PWS+S and PWS supplementation resulted in significantly greater AUC values than P in VO2 (PWS+S: 1,034±584; PWS: 802±434; P: 684±376; p=0.01); VCO2 (PWS+S: 1,372±604; PWS: 1,151±604; P: 634±262; p<0.01); and RER (PWS+S: 2.79±0.89; PWS: 2.44±0.98; P: 1.46±0.66; p<0.01). There were no significant interaction effects for HR (p=0.77), SBP (p=0....
BackgroundA number of nutritional strategies have been developed to optimize nutrient delivery prior to exercise. As a result, a number of pre-workout supplements have been developed to increase energy availability, promote vasodilation, and/ or positively affect exercise capacity. The purpose of this study was to examine the acute effects of ingesting a preworkout dietary supplement with and without synephrine on cognitive function, perceptions of readiness to perform, and exercise performance. MethodsIn a double-blind, crossover, randomized and placebocontrolled manner; 25 apparently healthy and recreationally active men and women (21.76±3.00 yr, 15.24±5.26% fat, 25.09±3.03 kg/m2) volunteered to participate in this study and performed a Stroup-Color cognitive function test (CFT) and rated perceptions of readiness to perform on a visual analogue scale (RTP-VAS). Participants then ingested in a randomized and counterbalanced manner a dextrose flavored placebo (P); a pre-workout supplement (PWS) containing 3.0 g beta alanine, 2 g creatine nitrate, 2 g arginine AKG, 300 mg of N-acetyl tyrosine, 270 mg caffeine, 15 mg of Mucuna pruriens; or, the PWS with 20 mg of synephrine (PWS+S). Approximately 30 minutes following ingestion of the supplements, participants performed a second CFT, completed a RTP-VAS, and then performed 3 sets of 10 repetitions at 70% of 1 repetition maximum (1RM) on the bench press and leg press with 2 minutes recovery between sets and 5 minutes recovery from exercise modes. Participants completed as many repetitions as possible during the final set. Following a 5-minute recovery, subjects also performed a 30-sec Wingate Anaerobic Capacity test on a cycle ergometer for determination of peak power (PP), mean power (MP), and total work (TW). Lastly, subjects performed a third CFT and RPT-VAS test. Participants repeated the experiment after a one week washout period with alternate supplements provided in a randomized and counterbalanced manner. Data were analyzed by repeated measure MAN-OVA or ANOVA and are presented as means ± SEM from baseline. Consent to publish the results was obtained from all participants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.