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Study Title and Description

Effect of caffeine on cycling time-trial performance in the heat.



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 Effect of caffeine on cycling time-trial performance in the heat.
Author NW Pitchford,JW Fell,MD Leveritt,B Desbrow,CM Shing,
Country
Year 2014
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 investigation was to determine whether a moderate dose of caffeine would improve a laboratory simulated cycling time-trial in the heat.
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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) Participants were nine highly trained male cyclists (22–42 years, body mass 73.56 ± 8.28 kg). Seven of the nine participants were regular caffeine consumers in the average range of 100–300 mg day−1. The research was con-ducted according to the National Statement on Ethical Conduct in Human Research (2007) (Australia) and was approved by the Tasmanian Human Research Ethics Committee (approval number H11654). Participants were recruited from cycling clubs around Northern Tasmania and were required to have a minimum of two years cycling experience. The study was a randomised, counterbalanced, double-blind, placebo-controlled, cross-over design. Cyclists attended the laboratory on four separate occasions including two experimental trials. Two experimental trials involving the consumption of either an anhydrous caffeine capsule (3 mg kg−1 BW) or a placebo capsule containing psyllium husk (Metamucil TM P&G Australia Pty Ltd., Sydney, NSW, Australia) 90 min prior to exercise were completed by each participant. Heart rate (HR) was recorded every 30 s of the test using a heart rate monitor (RS800CX, Polar Instruments Inc., Finland). Blood samples were obtained from the forearm antecubital space of each cyclist 90 min prior to exercise, 5 min pre-exercise and immediately post-exercise for analysis of plasma caffeine concentration. Prior to each trial, participants were asked to perform no physical activity, aside from activities of daily living, for 24 h before the start of each testing session and were provided with a 24 h pre-packaged diet including all food and fluid to be consumed before the trial and a standardised breakfast on the morning of each trial. The standardised diet was designed to minimise dietary differences across participants and between trials to ensure reliability, reproducibility and validity of time-trial results.21The pre-packaged diet provided 200 kJ kg−1BW and 7.5 g kg−1BW of carbohydrate for the day preceding the time-trials 40 kJ kg−1BW and 1.5 g kg−1BW of carbohydrate in the breakfast on the morning of time-trials. Participants were required to avoid alcohol for at least 24 h and caffeine for at least 12 h prior to each trial.
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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? RCT
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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) was recorded every 30 s of the test using a heart rate monitor (RS800CX, Polar Instruments Inc., Finland)."
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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.) Two experimental trials involving the consumption of either an anhydrous caffeine capsule (3 mg/kg) or a placebo capsule containing psyllium husk (Metamucil TM P&G Australia Pty Ltd., Sydney, NSW, Australia) 90 min prior to exercise were completed by each participant.
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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) To determine changes in bio-chemical variables in response to treatment condition a 2 (caffeine versus placebo) × 3 (pre-ingestion, pre-exercise and post-exercise) analysis of variance was conducted.
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What conflicts of interest were reported? "The authors have no conflicts of interest to declare."
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Refid 23932933
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What were the sources of funding? "There was no financial assistance received for this project."
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Results & Comparisons

No Results found.