title: Effects of acute ingestion of a pre-workout dietary supplement with and withoutp-synephrine on resting energy expenditure, cognitive function and exercise performance.
abstract: BACKGROUND
  The purpose of this study was to examine the effects of acute ingestion of a pre-workout dietary supplement (PWS) with and withoutp-synephrine (S) on perceptions of readiness to perform, cognitive function, exercise performance, and markers of safety.
  
  
  METHODS
  In a randomized, double-blind, and counterbalanced manner; 25 healthy and recreationally active male and female participants ingested a flavored maltodextrin placebo (PLA), a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg),Mucuna pruiriensextract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and Vitamin B12 as Methylcobalamin (70 mg) with 2 g of maltodextrin and flavoring; or, the PWS withCitrus aurantium(PWS + S) extract standardized for 30%p-synephrine (20 mg). Participants had heart rate (HR), blood pressure, resting energy expenditure (REE), 12-lead electrocardiograms (ECG), perceptions about readiness to perform, cognitive function (Stroop Color-Word test), bench and leg press performance (2 sets of 10 repetitions at 70% of 1RM and 1 set to failure), and Wingate anaerobic capacity (WAC) sprint performance determined as well as donated blood samples prior to and/or following exercise/supplementation. Data were analyzed by MANOVA with repeated measures as well as mean changes from baseline with 95% confidence intervals (CI).
  
  
  RESULTS
  No clinically significant differences were observed among treatments in HR, blood pressure, ECG, or general clinical blood panels. There was evidence that PWS and PWS + S ingestion promoted greater changes in REE responses. Participants reported higher perception of optimism about performance and vigor and energy with PWS and PWS + S ingestion and there was evidence that PWS and PWS + S improved changes in cognitive function scores from baseline to a greater degree than PLA after 1 or 2 h. However, the scores in the PWS + S treatment did not exceed PLA or PWS responses at any data point. No statistically significant differences were observed among treatments in total bench press lifting volume, leg press lifting volume or WAC sprint performance.
  
  
  CONCLUSIONS
  Within the confines of this study, ingestion of PWS and/or PWS + S prior to exercise appears to be well-tolerated when consumed by young, healthy individuals. The primary effects appear to be to increase REE responses and improve perceptions about readiness to perform and cognitive function with limited to no effects on muscular endurance and WAC. The addition of 20 mg ofp-synephrine to the PWS provided limited to no additive benefits.
  
  
  BACKGROUND
  This trial (NCT02952014) was retrospectively registered on September 13th 2016.
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Y Peter
authors.initials: YP
authors.lastname: Jung
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA ; Nutrabolt, Bryan, TX 77807 USA.
authors.forename: Conrad P
authors.initials: CP
authors.lastname: Earnest
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Koozehchian
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Elfego
authors.initials: E
authors.lastname: Galvan
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Dalton
authors.affiliation: Center for Translational Research in Aging and Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Dillon
authors.initials: D
authors.lastname: Walker
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rasmussen
authors.affiliation: Institute for Obesity Research & Program Evaluation, Department of Nutrition and Food Sciences, Texas A&M University, College Station, TX 77843 USA.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Murano
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Mike
authors.initials: M
authors.lastname: Greenwood
authors.affiliation: Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Kreider
mesh_terms: D003071:Cognition / Q000187:drug effects; D019587:Dietary Supplements; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000187:drug effects; D055070:Resistance Training; D064133:Sports Nutritional Physiological Phenomena; D013578:Synephrine / Q000008:administration & dosage* / Q000494:pharmacology; D016896:Treatment Outcome; D055815:Young Adult; D015091:beta-Alanine / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D015091:beta-Alanine; D013578:Synephrine
keywords: Dietary Supplement; Energy Drinks; Ergogenic Aids