Study Title and Description
Effects of caffeine and menthol on cognition and mood during simulated firefighting 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 behavior*?|
Primary Publication Information
|Title||Effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat.|
|Author||Y Zhang,G Balilionis,C Casaru,C Geary,RE Schumacker,YH Neggers,MD Curtner-Smith,MT Richardson,PA Bishop,JM Green,|
Secondary Publication Information
There are currently no secondary publications defined for this study.
Extraction Form: Behavior - Design Details - INCLUDED Studies
No arms have been defined in this extraction form.
|Question... Follow Up||Answer||Follow-up Answer|
|What outcome is being evaluated in this paper?||Behavior|
|What is the objective of the study (as reported by the authors)?||Therefore, this study examined the separate effects of caffeine and menthol on cognition and mood during a simulated firefighting exposure. We hypothesized that in a heat stress prolonged exercise condition, caffeine and menthol would increase cognitive performance and improve mood across time relative to placebo.|
|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)||2.1. Participants Ten males, unacclimatized to heat, volunteered to participate in this study. They were confirmed to be regular coffee drinkers, consuming at least one cup of regular coffee per day. Their physical characteristics were age: 24 _x0003_ 4 yr, height: 179 _x0003_ 6 cm,weight: 76.3 _x0003_ 15.3 kg, percentage of body fat: 8 _x0003_ 5%, and maximal oxygen uptake: 52.8 _x0003_ 5.3ml kg_x0004_1 min_x0004_1. This study was approved by the university’s Institutional Review Board for protection of human subjects. 2.2. Experimental design This study used a placebo-controlled, counter-balanced crossover repeated measures design. This study required participants to complete four laboratory visits. Experimental trials were conducted once per week. The first visit consisted of preliminary testing, workload assessment, and familiarization. The remaining three visits were experimental trials with placebo, caffeine, or menthol treatments. For the caffeine trial, caffeine was administered in capsule form (400 mg of caffeine) ten minutes prior to the 1st treadmill exercise. For the menthol and placebo trials, participants took menthol lozenges (10-mg menthol, 6-mg benzocaine) (Chloraseptic, Prestige Brands, USA), or placebo lozenges (6-mg benzocaine) (Cepacol Fizzlers, Combe Inc., USA). Each of the three trials consisted of a baseline assessment of cognition and mood (described below) followed by repeated post-treatment assessments. Participants took either one menthol lozenge (menthol trial) or placebo lozenge (caffeine and placebo trials) and entered the environmental chamber. They first completed a set of cognition tests (i.e., simple reaction test, followed by a short-term memory test, and math test) and a mood assessment. Then participants completed the 1st 20-min treadmill exercise, exited the environmental chamber, and completed the 1st 15-min rest period. Water was freely available during rest periods and volume consumed was recorded. A 2nd lozenge was taken prior to the 2nd treadmill exercise. Then participants repeated the 2nd 20-min treadmill exercise. Immediately after the 2nd treadmill exercise, participants completed another set of cognitions tests and mood assessment in the environmental chamber. Then participants exited the environmental chamber and completed the 2nd 15-min rest period. A 3rd lozenge was provided prior to the stepping exercise. Participants re-entered the environmental chamber and performed the stepping exercise. Immediately after the stepping exercise, participants completed the final set of cognition tests and a mood assessment in the environmental chamber. Upon doffing all gear except shorts, participants were weighed again at the end. 2.3.6. Mood Mood was assessed using 100-mm visual analogue rating scales (Smith et al., 1999). These 18 scales (e.g., Tense/Calm, Muzzy/Clearheaded, Antagonistic/Friendly) can be categorized into three factors: alertness, hedonic tone, and tension. Each factor score was calculated by summarizing the scores of the individual mood adjectives (e.g., Anxiety Mood = Relaxed/Excited + Troubled/Tranquil + Tense/Calm), and was later used in the statistical analysis. These scales are reported to be sensitive to caffeine administration for fatigued personnel (Smith et al., 1999). 2.4. Statistics analyses A repeated measures Analysis of Variance was used, and when a significant main effect was found, Fisher’s LSD was performed to identify specific differences. All values were reported as mean values and standard deviations. Statistical difference was considered to be significant at alpha _x0006_0.05.|
|How many outcome-specific endpoints are evaluated?||1|
|What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately)||tension|
|List additional health endpoints (separately).|
|List additional health endpoints (separately)|
|Notes||hedonic tone and alertness were also measured|
|What is the study design?||Controlled Trial|
|Randomized or Non-Randomized?||RCT|
|What were the diagnostics or methods used to measure the outcome?||Subjective|
|Optional: Name of Method or short description||visual analog scale|
|Caffeine (general)||Caffeine (general)|
|What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.)||placebo (0 mg caffeine) vs 400 mg caffeine|
|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|
|Provide a general description of results (as reported by the authors).||Exercise heat stress caused dramatic decreases in all three mood ratings (Fig. 3) (p < 0.05), but caffeine and menthol treatments did not significantly affect the mood compared to the placebo (p > 0.05).|
|Did the authors perform a dose-response analysis (or trend/related analysis)?||No|
|What were the authors's observations re: trend analysis?|
|What were the author's conclusions?||Furthermore, acute administration of caffeine or menthol presented no ergogenic effect on perceived exertion, cognition, or mood, at least under current test conditions of a high heat strain and a dynamic exercise protocol. However, neither caffeine nor menthol provided any positive effect on mood.|
|What were the sources of funding?||N/A|
|What conflicts of interest were reported?||N/A|
|Does the exposure (dose) need to be standardized to the SR?||No|
|Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).|
|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.||tension - NOAEL = 400 mg|
|Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot.||single dose no effects seen at levels mentioned in Nawrot.|
|What is the importance of the study with respect to the adverseness of the outcome?||Important|
No baseline characteristics have been defined for this extraction form.
Results & Comparisons
No Results found.
|Arm or Total||Title||Description||Comments|
No quality dimensions were specified.
No quality rating data was found.