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Study Title and Description

Influence of caffeine ingestion on perceived mood states, concentration, and arousal levels during a 75-min university lecture.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?
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Primary Publication Information
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TitleData
Title Influence of caffeine ingestion on perceived mood states, concentration, and arousal levels during a 75-min university lecture.
Author P Peeling,B Dawson,
Country
Year 2007
Numbers

Secondary Publication Information
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Extraction Form: Behavior - Design Details - INCLUDED Studies
Arms
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Design Details
Question... Follow Up Answer Follow-up Answer
Refid 18057405
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What outcome is being evaluated in this paper? Behavior
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What is the objective of the study (as reported by the authors)? As such, the purpose of this investigation was to assess the effect of a caffeine supplement on perceived mood state, concentration, and arousal during a 75-min university lecture.
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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) Subjects. Ten third-year Human Movement and Exercise Science students from the University of Western Australia were recruited for participation in this study. All subjects were briefed on the purpose, requirements, and risks involved with participation in this investigation. Written informed consent was signed in accordance with the Human Ethics Committee of The University of Western Australia. Experimental overview. This investigation was a randomized, blind, cross-over design that ran over a course of 2 consecutive weeks. During week 1, 10 third-year Human Movement and Exercise Science students, all considered to be regular caffeine consumers (consumption of 1 or 2 caffeinated products daily) were assigned to either a caffeine- or placebo-supplemented group and were subsequently required to attend a 75-min exercise rehabilitation lecture. Seven days later, students were assigned to the opposite supplementation group before attending a second follow-on lecture, equal in duration to that of week 1. In the 24 h prior to the commencement of each lecture, all students were asked to abstain from the consumption of any caffeinated products. On the morning of each lecture, all participants were required to attend the venue 60 min prior to its commencement. At this point, the caffeine-supplemented group was supplemented with 100 mg caffeine, an amount approximately equivalent to 1 cup of peculated coffee or two 350-ml cans of soft drink (5). Additionally, the placebo supplemented group was supplemented with 100 mg NaCl. Supplements were given to the participants in the form of identically sized white pills covered by a gelatin capsule to disguise any taste that may result from the content of the pills. Participants were supplemented 60 min prior to the lecture, since it has been suggested that peak blood concentrations of caffeine occur _x0003_1 h post-supplementation (1, 6). Sixty minutes later, all subjects attended a 75-min exercise rehabilitation lecture. At the conclusion of the 75-min period, participants were given a mood perception questionnaire to assess the perceived level of mood state, concentration, and arousal during the lecture. Questionnaire. The student perception questionnaire used in this investigation was divided into two sections. Section 1 was based on the mood questionnaire employed previously by Leatherwood and Pollet (15) to assess the effects of caffeine on subjective sensations. To complete this questionnaire, each participant was asked to give an indication of how they felt during the 75-min lecture by rating seven adjectives (awake, clear minded, energetic, creative, alert, anxious, and efficient) on a 7-point Likert Scale. Additionally, section 2 asked each participant to rate their perceived level of arousal and concentration during the lecture period on a 10-point Likert Scale. Statistical analysis. All data was analyzed with paired-samples t-tests using the Excel for Windows computer software package. Statistical significance was accepted at an _x0004_-level of P _x0001_ 0.05. Data are expressed as means _x0002_ SE.
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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) anxiety
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List additional health endpoints (separately).
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List additional health endpoints (separately)
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Notes other mood states evaluated were: awake, clear minded, energetic, creative, alert, and efficient.
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Clinical
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Physiological
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Other
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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? Subjective
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Optional: Name of Method or short description mood questionnaire previously used by Leatherwood and Pollet
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Caffeine (general) Caffeine (general)
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Coffee
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Chocolate
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Energy drinks
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Gum
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Medicine/Supplement
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Soda
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Tea
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Measured Measured
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Self-report
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Children
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Adolescents
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Adults Adults
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Pregnant Women
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) placebo (NaCl, no caffeine) vs 100 mg caffeine
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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) N/A
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Provide a general description of results (as reported by the authors). The results showed that after caffeine consumption, students perceived themselves to be significantly more awake (P =_x0005_ 0.01), clear minded (P =_x0005_ 0.03), energetic (P =_x0005_ 0.02), alert (P _x0005_ 0.05), and anxious (P= _x0005_ 0.03) than after consuming the placebo.
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Did the authors perform a dose-response analysis (or trend/related analysis)? No
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What were the authors's observations re: trend analysis?
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What were the author's conclusions? The results of this investigation suggest that a low dose of caffeine (100 mg), consumed 60 min prior to the commencement of a 75-min university lecture, can enhance a student’s perception of specific behavioral functions and mood states that are vital to learning. Specifically, these results show that students feel significantly more awake, clear minded, energetic, alert, anxious, concentrated, and aroused as a result of caffeine supplementation. Since caffeine is a stimulant, the increased levels of anxiety reported from our students should be expected. However, rather than having a negative impact on mood state during a lecture, it is possible that the greater anxiety levels were actually beneficial as a result of an increased NE drive. Furthermore, the increased levels of anxiety seen from our sample population support the findings of Smith et al. (21), who also showed greater feelings of anxiety with consumption of a low-dose caffeinated beverage.
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What were the sources of funding? None listed
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What conflicts of interest were reported? N/A
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Does the exposure (dose) need to be standardized to the SR? No
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Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).
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List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot.  Characterize value as LOAEL/NOAEL, etc. if possible.  Anxiety - LOAEL = 100 mg/day
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. single dose Effect seen at levels below Nawrot. Appears to be a small magnitude change.
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What is the importance of the study with respect to the adverseness of the outcome? Important
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