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Study Title and Description

Effect of caffeine on LT, VT and HRVT.



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 Effect of caffeine on LT, VT and HRVT.
Author GK Karapetian,HJ Engels,KA Gretebeck,RJ Gretebeck,
Country
Year 2012
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)? The purpose of this investigation was to determine the influence of caffeine on lactate, ventilatory, and heart rate variability thresholds during progressive exercise.
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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 Polar ® HR monitor (Polar, Vantage XL, Woodbury, NY, USA) was used to record RR intervals throughout the test to an accuracy of 1 ms (digitized signal at 1 000 Hz). RR interval data were stored in a receiving watch, and subsequently uploaded to a computer for analysis using Polar ® Heart Rate monitoring software, then analyzed on an Excel spreadsheet following previously determined formulas. Heart rate variability threshold was determined by using the time domain indices standard deviation (SD), coefficient of variation (CV), and mean successive difference (MSD), which have been shown to correlate strongly with vagal tone (r = 0.87, 0.81, and 0.92 respectively; p < 0.001); just as the frequency domain indices of autoregressive spectrum analysis [ 19 ]. uses the same type of visual technique used to determine LT, requires fewer RR intervals for analysis, and can be calculated using a standard computer spreadsheet making the technique simple to use and understand [ 22 ] . The RR intervals from the last 2 min of rest and each stage of exercise were used for analysis of HRV. The last 2 min were used to ensure an adequate number of R-R intervals were collected. Data were separated by stage, and automatically filtered to eliminate missing or premature beats. The RR intervals were designated as premature beats if they deviated from the previous eligible interval by > 30 % [ 36 ] . To determine HRVT during graded exercise testing, time domain indices of HR intervals for each stage of exercise were graphically plotted against work rate (W). Then, in a manner similar to the determination of LT and VT, a visual interpretation was made to locate the point at which there was no further decline in HRV, thus indicating vagal withdrawal. This point was defined as the HRVT [ 22 ] .
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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 (heart rate, heart rate coefficient of variation, standard deviation, and mean successive differences)
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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 Polar ® HR monitor (Polar, Vantage XL, Woodbury, NY, USA) was used to record RR intervals throughout the test to an accuracy of 1 ms (digitized signal at 1 000 Hz). RR interval data were stored in a receiving watch, and subsequently uploaded to a computer for analysis using Polar ® Heart Rate monitoring software, then analyzed on an Excel spreadsheet following previously determined formulas. Product used: anhydrous caffeine (Firma Caesar & Loretz, Hilden, Germany), which was dissolved in 250 ml of caffeine-free diet cola, or the placebo, which was the same caffeine-free diet cola without the added caffeine. Subjects then rested quietly in the laboratory until data acquisition began. Heart rate variability threshold was determined by using the time domain indices standard deviation (SD), coefficient of variation (CV), and mean successive difference (MSD), which have been shown to correlate strongly with vagal tone (r = 0.87, 0.81, and 0.92 respectively; p < 0.001); just as the frequency domain indices of autoregressive spectrum analysis [ 19 ]. uses the same type of visual technique used to determine LT, requires fewer RR intervals for analysis, and can be calculated using a standard computer spreadsheet making the technique simple to use and understand [ 22 ] . The RR intervals from the last 2 min of rest and each stage of exercise were used for analysis of HRV. The last 2 min were used to ensure an adequate number of R-R intervals were collected. Data were separated by stage, and automatically filtered to eliminate missing or premature beats. The RR intervals were designated as premature beats if they deviated from the previous eligible interval by > 30 % [ 36 ] . To determine HRVT during graded exercise testing, time domain indices of HR intervals for each stage of exercise were graphically plotted against work rate (W). Then, in a manner similar to the determination of LT and VT, a visual interpretation was made to locate the point at which there was no further decline in HRV, thus indicating vagal withdrawal. This point was defined as the HRVT [ 22 ] .
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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 vs caffeine treatment
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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 subjects were characterized using descriptive data analysis. Caffeine vs. placebo data were analyzed using one-way repeated measures analysis of variance (ANOVA) in SPSS version 15.0 (SPSS Inc., Chicago, IL, USA). The study was a within subjects design, where each subject served as her/his own control for the test-retest procedure. Significant effects were followed up by Duncan’s multiple range test for post hoc comparisons. Pearson’s correlation was used to evaluate the respective associations between the oxygen consumption at which HRVT occurred for CV, SD and MSD.
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What conflicts of interest were reported? Not discussed.
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Refid 22499570
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What were the sources of funding? Not discussed.
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Results & Comparisons

No Results found.