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Study Title and Description

Acute effects of caffeine on heart rate variability.



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 Acute effects of caffeine on heart rate variability.
Author HP Sondermeijer,AG van Marle,P Kamen,H Krum,
Country
Year 2002
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 present study sought to determine the effect of acute caffeine ingestion on PNSA in nonhabitual caffeine users.
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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) Nonhabitual caffeine users (<1 dose/day) aged >/=18 years were studied. Any clinically relevant medical condition, need for regular medication, current cigarette smoking, or alcohol abuse was an exclusion to entry. Ten subjects (6 men and 4 women, mean age 26 years [range 23 to 32]) were randomized in a 3-way, single-blind, crossover study design to receive single oral doses of placebo or 100 or 200 mg of caffeine dissolved in honey. A minimum 4-day washout period was mandated to minimize any carryover effects as well as the potential for effects of caffeine withdrawal. On each study day, heart rate, blood pressure, and PNSA were measured before administration of caffeine/placebo as well as during the period 60 to 90 minutes after ingestion. Blood pressure was measured by a Dinamap (Critikon, Arlington, Texas) semiautomated blood pressure monitor. Three measurements were averaged for each blood pressure determination. PNSA was determined from analysis of heart rate variability (HRV). Computerized electrocardiographic recordings were converted into a scatter plot of the current cardiac cycle length (RR interval) against the immediately preceding RR interval (Poincare´ plot). The time-domain parameters of HRV evaluated were SD of RR intervals, root-mean-squared difference in successive RR intervals, and percentage of successive RR intervals >50 ms different from one another. The frequency domain parameter of HRV evaluated was high-frequency power (0.15 to 0.40 Hz). The above HRV measures are generally accepted as reflecting cardiac PNSA. Sympathovagal balance was assessed by low-frequency power/high-frequency power ratio. Blood pressure, HRV, and alertness values for changes in 100 and 200 mg of caffeine from baseline were compared with placebo by 1-way analysis of variance. All values are expressed as mean +/- SEM. A 2-tailed p value <0.05 was considered statistically significant.
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (SBP and DBP)
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List additional health endpoints (separately). 2 Heart rate
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List additional health endpoints (separately).3 Heart rate variability (SD of RR intervals [SDNN], root-mean squared difference in successive RR intervals [rMSSD], percentage of RR intervals >50 ms from one another [pNN50 (%)], high-frequency power [HFP], and low frequency power to high frequency power ratio [LFP/HFP]
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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 Blood pressure was measured by a Dinamap (Critikon, Arlington, Texas) semiautomated blood pressure monitor. Three measurements were averaged for each blood pressure determination. For HRV, computerized electrocardiographic recordings were converted into a scatter plot of the current cardiac cycle length (RR interval) against the immediately preceding RR interval (Poincare´ plot).
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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.) Each person appears to have served as their own controls; however, the text is confusing. Baseline measurements were taken before treatment; however, measurements after treatment were "placebo-corrected" before being compared to baseline.
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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) None
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What conflicts of interest were reported? No information provided
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Refid 12372588
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What were the sources of funding? No information provided
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Results & Comparisons

No Results found.