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Study Title and Description

Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals.



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 Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals.
Author E Childs,H de Wit,
Country
Year 2008
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)? This study compared the effects of a caffeine-containing (200 mg) supplement or placebo in capsule form after prolonged wakefulness, in participants who varied in their level of habitual caffeine use.
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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) Study design: Male (n=16) and female (n=19) volunteers aged 18–35 were recruited, without regard to race or ethnicity, from the university and surrounding community via posters, newspaper advertisements, and word-of-mouth referrals. Study design: Participants completed questionnaires that detailed current and prior drug use history. Individuals attended an orientation study at which the study procedures were explained, and they read and signed a consent form that detailed the study procedures. Subjects also practiced completing the self-report questionnaires and behavioral tasks to familiarize themselves with the study procedures and tasks. The consent form explained that the study was designed to investigate the effects of drugs upon mood and performance after prolonged wakefulness. Experimental procedure: On the morning of each session, participants were required to wake at 7:00 a.m. and remain awake throughout the day and throughout the nighttime session. Compliance with the waking requirements was monitored with the use of wrist activity monitors. On arrival at the laboratory at 5:00 p.m., subjects provided breath and urine samples to test for recent drug and alcohol use. No subjects tested positive. All records demonstrated that participants woke at 7:00 a.m. and remained awake throughout the day. Vital signs (blood pressure and heart rate) were also obtained. At 3:00 a.m., participants were given a heart rate monitor to wear that measured their heart rate continuously. They completed subjective questionnaires and behavioral tasks at 3:00 a.m., and baseline vital signs were measured. At 3:30 a.m., participants consumed a capsule that was caffeine or placebo. Participants completed behavioral tasks 30 min after the capsule at 4:00 a.m., and mood and cardiovascular measures were recorded every 30 min until 5:00 a.m. At 5:00 a.m., after final measures had been obtained, participants were allowed to leave the laboratory and were provided with transport home.
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How many outcome-specific endpoints are evaluated? 2
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (systolic and diastolic)
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List additional health endpoints (separately). 2 Heart rate
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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 was measured continuously with the use of a chest band and Mini Mitter system (Mini-Logger® Series 2000, Mini Mitter Co.). Blood pressure was measured at repeated intervals with the use of a digital monitor (Dinamap 1846SX, Critikon, Tampa, FL).
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? Medicine/Supplement
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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.) Individuals served as their own controls; placebo vs. caffeine supplement-exposed.
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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) Behavioral, cardiovascular, and subjective scores at 5:00 p.m. and 3:00 a.m. (before capsule administration) were analyzed with the use of two- (within-subjects) factor (Session Number x Time) repeated-measures ANCOVA with average caffeine consumption as a covariate. Drug effects upon subjective and cardiovascular measures were expressed as the peak change from measures obtained at 3:00 a.m. Drug effects were examined with the use of one- (within-subjects) factor (Drug) repeated-measures ANCOVA with average caffeine consumption and session order as covariates. Where there were no significant main effects or interactions of a covariate with drug treatment they were dropped from the analysis.
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What conflicts of interest were reported? There were no conflicts of interest according to the authors.
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Refid 18266548
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What were the sources of funding? Research was supported by a grant from Atlas Labs USA and NIDA.
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