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Study Title and Description

A moderate dose of caffeine ingestion does not change energy expenditure but decreases sleep time in physically active males: a double-blind randomized controlled trial.



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 A moderate dose of caffeine ingestion does not change energy expenditure but decreases sleep time in physically active males: a double-blind randomized controlled trial.
Author PB Júdice,JP Magalhães,DA Santos,CN Matias,AI Carita,PA Armada-Da-Silva,LB Sardinha,AM Silva,
Country
Year 2013
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)? Research on the effect of caffeine on energy expenditure (EE), physical activity (PA), and total sleep time (TST) during free-living conditions using objective measures is scarce. We aimed to determine the impact of a moderate dose of caffeine on TST, resting EE (REE), physical activity EE (PAEE), total EE (TEE), and daily time spent in sedentary, light, moderate, and vigorous intensity activities in a 4-day period and the acute effects on heart rate (HR) and EE in physically active males.
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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) A total of 30 healthy young adult males aged between 20 and 39 years volunteered to participate in this study. Inclusion criteria were body mass index (BMI) between 18.5 and 29.9 kg/m2, nonsmokers, and not taking any medications or dietary supplements that may affect energy expenditure. In addition, participants were low-caffeine users (<100 mg/day) (Currie et al. 1995). The daily consumption of caffeine was estimated based on self-report of daily intakes of coffee, tea, caffeinated sodas, and other dietary sources. All participants were informed about the possible risks of the investigation before giving their written informed consent to participate. Two hours after the dose administration, participants needed to (i) be engaged in sedentary behaviors (<100 counts/min) measured by accelerometry and (ii) display a complete time registration during the 2 h after dose administration, with no heart rate (HR) data lost, interpolated, or recovered from the combined HR and movement sensor registration. It is important to underline that these criteria were considered to compare HR and EE under caffeine or placebo conditions to reduce the potential effect of habitual PA on HR and EE. However, we did try to reduce the variability of PA patterns by performing both conditions on the same weekdays. As a result, only 14 participants were eligible for this analysis. The characteristics of this subsample were generally similar to the initial sample. After the participants were weighed, the dose was individually prepared to assure that 5 mg of caffeine per kilogram of body mass per day was administered. The dose of caffeine was divided into two equal parts (2.5 mg/kg) to be orally consumed through capsules in the morning and after lunch. An equivalent number of placebo capsules, of the same colour as the caffeine capsules, containing maltodextrin were provided for the placebo condition. a new generation of motion sensors that combines a HR monitor with an accelerometer was used to assess the acute effects of caffeine ingestion on HR and EE after the second hour of administration in those participants considered sedentary based on accelerometry data collection (<100 counts/min). The free-living EE and HR on the second hour after caffeine and placebo ingestion were assessed using a combined HR and movement sensor using different energy models, available in the commercial software (Actiheart, CamNtech Ltd, UK). Subsequently, free-living HR and acceleration were measured in 1-min epochs, which allowed the use of the combined sensor during the whole study period. However, for this particular assessment, only the second hour after the ingestion of caffeine and placebo was analyzed. The monitors should only be removed for showering, bathing, or activities such as swimming. Data downloading, processing, and analysis were performed using the Actiheart commercial software using the advance energy expenditure mode. HR Flex using the individual HR calibration model was used to estimate EE from PA as specified by the Actiheart software (Brage et al. 2007). The magnitudes of both HR and EE on the second hour after administration (caffeine and placebo), previously described at the experimental design, were compared with a reference hour obtained as the lowest HR and EE values assessed during the REE measurement. Along with the use of this combined motion sensor and HR equipment, participants were provided with a worksheet to record the type and duration of the physical activities performed.
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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 A new generation of motion sensors that combines a HR monitor with an accelerometer was used to assess the acute effects of caffeine ingestion on HR and EE after the second hour of administration in those participants considered sedentary based on accelerometry data collection (<100 counts/min). The free-living EE and HR on the second hour after caffeine and placebo ingestion were assessed using a combined HR and movement sensor using different energy models, available in the commercial software (Actiheart, CamNtech Ltd, UK).
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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.) Placebo (maltodextrin, 0 mg caffeine) vs. 5 mg/kg caffeine (2 x 2.5 mg/kg per day)
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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) Inclusion criteria were body mass index (BMI) between 18.5 and 29.9 kg/m2, nonsmokers, and not taking any medications or dietary supplements that may affect energy expenditure. To compare the effects of caffeine on mean values of the dependent variables (TST, HR, TEE, PAEE, REE, ST, LPA, MPA, and VPA), a repeated measures analysis of variance (ANOVA) was used. The Mauchly's sphericity test was performed to examine the form of the common covariance matrix, i.e., if p > 0.05, the spherical matrix has equal variances and covariances equal to zero. Further analyses were only conducted if the common covariance matrix of the transformed within-participant variables was spherical, otherwise, the F tests and associated p values for the univariate approach to testing within-subject hypotheses would be invalid. Analysis of co-variance (ANCOVA) for crossover trials was performed as recommended by Senn et al. (1993). Paired sample t test was performed to analyze food intake between the two conditions.
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What conflicts of interest were reported? N/A
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Refid 23368828
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What were the sources of funding? This work was supported by the Hydration and Health Portuguese Institute,
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