title: The effects of a single-dose thermogenic supplement on resting metabolic rate and hemodynamic variables in healthy females--a randomized, double-blind, placebo-controlled, cross-over trial.
abstract: BACKGROUND
  Recent investigations have identified that commercially available dietary supplements, containing a combination of thermogenic ingredients, can increase resting metabolic rate (RMR). Thermogenic dietary supplements can have a positive influence on RMR, but the magnitude can vary based on the active ingredient and/or combination of active ingredients. Additionally, further safety evaluation is needed on multi-ingredient supplements that contain caffeine, due to its potential effect on heart rate (HR) and blood pressure (BP). The purpose of this study was to examine the effects of a commercially available dietary supplement on RMR and hemodynamic variables in healthy females.
  
  
  METHODS
  13 female participants (26.1 ± 11.3 years; 163.4 ± 9.1 cm; 63.7 ± 8.0 kg, and 24 ± 5 BMI) volunteered to participate in this investigation. Participants underwent two testing sessions separated by approximately 7 days. On their first visit, participants arrived to the laboratory after an overnight fast and underwent a baseline RMR, HR, and BP assessment. Next, each participant ingested a thermogenic dietary supplement or placebo and repeated the RMR, HR, and BP assessments at 60, 120, and 180-minutes post-ingestion. Approximately 1-week later, the alternative supplement was ingested and the assessments were repeated in the exact same manner. Data were analyzed via a 2-factor [2x4] within-subjects repeated measures analysis of variance (ANOVA). Post-hoc tests were analyzed via paired samples t-tests.
  
  
  RESULTS
  Repeated measures ANOVA revealed a significant effect for time relative to raw RMR data. Post-hoc analysis revealed that the dietary supplement treatment significantly increased RMR at 60-minutes, 120-minutes, and 180-minutes post ingestion (p < 0.05) as compared to baseline RMR values. No changes in RMR were observed for the placebo treatment (p > 0.05). Heart rate was not significantly affected at any time point with either supplement; however, main effects of treatment and time were observed for both systolic and diastolic blood pressure (p < 0.05).
  
  
  CONCLUSIONS
  The thermogenic dietary supplement treatment experienced greater elevations in RMR as compared to baseline. Due to the slight elevations in blood pressure, caution should be taken for those with increased risk for hypertension or pre-hypertension. Taken on a daily basis, thermogenic dietary supplementation may increase overall energy expenditure, potentially leading to reductions in fat mass over time.
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Bill I
authors.initials: BI
authors.lastname: Campbell
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Gina
authors.initials: G
authors.lastname: Zito
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Colquhoun
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Nic
authors.initials: N
authors.lastname: Martinez
authors.affiliation: Bodybuilding.com, Boise, ID 83713 USA.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kendall
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Buchanan
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Matt
authors.initials: M
authors.lastname: Lehn
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Mallory
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Courtney
authors.initials: C
authors.lastname: St Louis
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Smith
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Brad
authors.initials: B
authors.lastname: Cloer
authors.affiliation: Exercise Science Program, Performance & Physique Enhancement Laboratory, College of Education, University of South Florida, Tampa, FL 33620 USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Pingel
mesh_terms: D000704:Analysis of Variance; D001481:Basal Metabolism / Q000187:drug effects* / Q000502:physiology; D002153:Calorimetry, Indirect; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D005082:Physical Exertion / Q000187:drug effects*; D012146:Rest / Q000502:physiology; D022722:Thermogenesis / Q000187:drug effects*; D016896:Treatment Outcome
keywords: Dietary supplement; Fat loss; Female physique enhancement; Metabolism; Sports nutrition; Weight loss