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Study Title and Description

Evaluation of experience-based fatigue countermeasures.



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 Evaluation of experience-based fatigue countermeasures.
Author P Gershon,D Shinar,A Ronen,
Country
Year 2009
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)? Strategies adopted by drivers in order to cope with fatigue and falling asleep at the wheel include a variety of activities that may invigorate the body and/or the mind. The objectives of the current study were to examine the effectiveness of an energy drink and a non-traditional manual dexterity/mastication activity as fatigue countermeasures.
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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: A total of 20 healthy male (65%) and female (35%) Israeli undergraduate students (aged 23–30, median = 25) with at least 5 years of driving experience were paid a student fee of $5 an hour for participation in the study. They were recruited by advertisements on university billboards. All were non-smokers and moderate caffeine consumers (maximum of 1–3 cups of coffee per day), with body mass index (BMI) of 18.5–25 kg/m2, and all reported shelling and eating sunflower seeds occasionally. Procedure: Each subject participated in seven sessions consisting of 1-h long orientation session and three pairs of morning and evening 2-h driving sessions, one pair of sessions for each treatment condition. The morning session for all subjects was from 7:00am to 9:00 am, and the evening session (on the same day) was from 5:00 pm to 7:00 pm. Thus, the study consisted of a total of 260 h of simulated driving. The subjects received a list of instructions pertaining to the nights before the experimental sessions. On the night before the experiment they were instructed to get a good night sleep of 7–8 h and avoid alcohol consumption. On the day of the experiment they were instructed to avoid consumption of any products containing caffeine, naps and intensive sport activity. Lunch provided to the subjects as part of the protocol contained no caffeine and no meat. Each experimental session consisted of the following five stages: (I) Filling out a pre-drive fatigue questionnaire (SOFI-20–Swedish Occupational Fatigue-20 Inventory). (II) 10 min rest period in the car with the eyes closed while the physiological monitoring systemwas hooked up. Documenting the initial physiological state of the driver. (III) 120min drive at the driver’s preferredspeed, without exceeding the 55mph posted speed limit. (IV) 10 min recovery consisting of remaining seated in the car with the eyes closed. Documenting the physiological state of the driver after the prolonged drive ended. (V) Disconnecting the physiological electrodes and filling out a post-drive SOFI-20. Equipment: A physiological monitoring system consisting of a multichannel polygraph synchronized with the simulation program, recorded the driver’s ECG. Special software was used to analyze the R–R peaks in order to derive heart rate variability (HRV) and heart rate (HR). Design: The study design was within subjects, with the order of the treatments (MD/DT, energy drink, and control) counterbalanced across subjects. On each day that a subject participated in the study, the same treatment was evaluated in a morning and an evening session. Treatments: Energy drink. The subject was required to drink two 250-ml cans of a commercially available energy drink over a 10-min period as soon as he/she arrived to the lab. Together the two cans have the same amount of caffeine that is contained in one strong cup of coffee, an amount that has been shown to improve performance and increase alertness of fatigued people (Horne and Reyner, 1999). All subjects started the drive after 20 min from intake. The energy drink was only given in the morning session to see if there are any negative residual effects in the evening session. Each can of energy drink contained: 21 g sucrose, 5 g glucose, 1 g taurine, 80mg caffeine, 600mg glucuronolactone, 50mg insositol, and vitamin B complex. Control treatment. In this session the subjects received the same drinking volume as in the treatments sessions. The drinks were glucose-free diet drinks that had a similar taste and color to that of the energy drink but without the active ingredients of caffeine, taurine, glucuronolactone, sugar, and vitamin B.
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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 variability
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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 Equipment: A physiological monitoring system consisting of a multichannel polygraph synchronized with the simulation program, recorded the driver’s ECG. Special software was used to analyze the R–R peaks in order to derive heart rate variability (HRV) and heart rate (HR).
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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.) Glucose-free diet drink that had similar taste and color as energy drink but without caffeine and other ingredients.
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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) The driving performance measurements were calculated for four consecutive phases in each session. Each driving performance measure was analyzed using a three-way ANOVA for repeated measures (PhasexTreatmentxTime of day) followed by post hoc Fisher LSD pair-wise comparisons to identify the source of significant effects. For the subjective questionnaire the difference score between the level reported after the drive and the level reported before the drive was first calculated. The difference scores were analyzed using two-way ANOVAs for repeated measures, also followed by post hoc Fisher LSD pair-wise comparisons. Heart Rate Variability was calculated for five consecutive phases in each session: "Rest" before the drive, "Baseline" in the beginning of the drive, three blocks of 36.6 min long driving phases, and "Recovery" in the car after the drive. Heart rate variability was normalized for each session separately according to the "Baseline" that was given a score of 100%. The normalized HRV scores were analyzed using a three-way ANOVA for repeated measures (PhasexTreatmentxTime of day).
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What conflicts of interest were reported? Conflicts were not discussed.
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Refid 19664434
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What were the sources of funding? This study was supported in part by a contract from the National Highway Traffic Safety Administration, U.S. Department of Transportation, and by the Paul Ivanier Center for Robotics and Production Management, Ben Gurion University of the Negev.
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Results & Comparisons

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