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Study Title and Description

Independent and combined effects of carbohydrate and caffeine ingestion on aerobic cycling performance in the fed state.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title Independent and combined effects of carbohydrate and caffeine ingestion on aerobic cycling performance in the fed state.
Author TL Acker-Hewitt,BM Shafer,MJ Saunders,Q Goh,ND Luden,
Country
Year 2012
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? The purpose of this study was to examine the independent and combined effects of carbohydrate and caffeine ingestion on performance and various physiological parameters during aerobic cycling (about 1 hour).
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) The 4 treatments were (i) placebo (PLA) trial: placebo pill administered 60 min prior to exercise, and artificially sweetened water (250 mL) administered at the following 3 time points during the exercise trial: immediately prior to exercise, following the 20-min SS (steady state), and 20 min into the TT (time trial); (ii) carbohydrate- only (CHO) trial: placebo pill administered 60 min prior to exercise, and a carbohydrate solution (20 g carbohydrate, 8% solution, 250 mL fluid) administered at the 3 aforementioned time points; (iii) caffeine-only (CAF) trial: 6-mg/kg body weight dose of commercially available anhydrous caffeine (TerraVita; in pill form) administered 60 min prior to exercise, and a placebo solution containing artificially sweetened water (250 mL) administered at the 3 time points; and (iv) caffeine and carbohydrate (CAF-CHO) trial: 6-mg·kg–1 body weight caffeine pill administered 60 min prior to exercise, and a carbohydrate solution (20 g carbohydrate, 8% solution, 250 mL fluid) administered at the 3 time points. Heart rate (HR) (Polar, Lake Success, N.Y., USA) and rating of perceived exertion (RPE) (Borg scale) were recorded in the eighth minute of the 20-min SS segment and with 0.05 km remaining in the 20-km TT.
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How many outcome-specific endpoints are evaluated? 1
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Heart rate
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List additional health endpoints (separately). 2
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List additional health endpoints (separately).3
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? NCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Heart rate (HR) (Polar, Lake Success, N.Y., USA) and rating of perceived exertion (RPE) (Borg scale) were recorded in the eighth minute of the 20-min SS (steady state) segment and with 0.05 km remaining in the 20-km TT (time trial).
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) placebo vs. caffeine treatment
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) Duration and mean power output (W) for the 20-km TT, HR, RPE, RER, blood glucose, decline in MVC (pre- to postexercise), and blood lactate were assessed using repeated- measures analyses of variance (ANOVA), with treatment as a within-subjects factor. A 2 x 4 (time x treatment) repeated-measures ANOVA was used to assess pre- and postexercise MVC. Further, planned comparisons for both TT performance and mean power output were identified a priori and included each treatment compared with PLA. All pairwise comparisons were performed using dependent t tests with a Bonferroni correction. Friedman tests were applied to the following parameters that were not normally distributed: V O2, VE, RPE, post-TT glucose, and lactate. Pairwise comparisons were performed using Wilcoxon’s signed Rank Tests. The a priori level of significance was set at p < 0.05. All data are reported as means +/- SD.
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What conflicts of interest were reported? Not discussed.
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Refid 22436075
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What were the sources of funding? Not discussed.
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