Original Contribution
Cardiovascular responses to energy drinks in a healthy population: The C-energy study,☆☆

https://doi.org/10.1016/j.ajem.2016.02.068Get rights and content

Abstract

Background

Energy drink consumption has increased significantly over the past decade and is associated with greater than 20,000 emergency department visits per year. Most often these visits are due to cardiovascular complaints ranging from palpitations to cardiac arrest.

Objective

To determine if energy drinks alter; blood pressure, electrolytes, activated bleeding time (ACT), and/or cardiac responses measured with a 12-lead electrocardiographic (ECG) Holter.

Methods

Continuous ECG data was collected for five hours (30 minutes baseline and 4 hours post consumption [PC]). Subjects consumed 32 ounces of energy drink within one hour and data (vital signs and blood samples) was collected throughout the study period. Paired students t-test and a corresponding non-parametric test (Wilcoxon signed rank) were used for analysis of the data.

Results

Fourteen healthy young subjects were recruited (mean age 28.6 years). Systolic blood pressure (baseline = 132, ± 7.83; PC = 151, ± 11.21; P = .001); QTc interval (baseline = 423, ± 22.74; PC = 503, ± 24.56; P < .001); magnesium level (baseline 2.04, ± 0.09; PC = 2.13, ± 0.15; P = .05); and calcium level (baseline = 9.31, ± .28; PC = 9.52, ± .22; P = .018) significantly increased from baseline. While potassium and ACT fluctuated (some subjects increased their levels while others decreased) these changes were not significant. Eight of the fourteen subjects (57%) developed a QTc > 500 milliseconds PC. Other T-wave changes were noted in 9/14 (64.3%) subjects PC.

Conclusions

Energy drinks increased systolic blood pressure, altered electrolytes, and resulted in repolarization abnormalities. These physiological responses can lead to arrhythmias and other abnormal cardiac responses highlighting the importance that emergency room personnel assess for energy drink consumption and potential toxicity.

Introduction

Energy drinks are beverages containing caffeine and other herbal supplements such as Panax ginseng, guarana, and other vitamin and minerals. Each manufacturer of these drinks has their own proprietary blend of additives; ingredients are listed on the label but volumes or percentages of each are not. These drinks are marketed as an aid to improve athletic performance, enhance concentration, and increase energy and weight loss [1], [2]. The first energy drink was introduced in the United States in 1997 [3] and by 2016, sales are expected to reach $52 billion [4]. Reported emergency department visits secondary to energy drinks skyrocketed from just over 1000 in 2005 to more than 20,000 in 2011 [4], [5]. Most often, these visits are due to a cardiac issue ranging from rapid heart rate, palpitations, myocardial infarction, stroke, and even cardiac arrest [6], [7], [8], [9], [10]. Recent studies have demonstrated that energy drink consumption may lead to altered platelet aggregation [11], [12] altered endothelial function [12] increased systolic blood pressure and prolonged QTc intervals [6], [13], [14], [15], suggesting a cardiovascular response that may lead to these pathologies.

Studies to date, have examined the electrocardiogram (ECG) at incremental periods of time post energy drink consumption. We hypothesized that ECG changes may occur at different time periods which could lead to cardiac pathologies and conditions after the consumption of an energy drink. Little is known about the possible mechanisms seen in patients who develop serious cardiovascular conditions associated with energy drink consumption. As a first step to better understand the cardiac response to energy drink consumption, we conducted the C-Energy study (Cardiovascular rEspoNses to EneRGy drinks in a healthy population) to determine if energy drinks alter: blood pressure, electrolytes (magnesium, potassium, calcium), activated bleeding time, and/or the ECG measured with 12-lead ECG Holter.

Section snippets

Methods

This was a prospective observational study to examine cardiovascular responses to energy drink consumption in healthy subjects 18–40 years old who were not energy drink naïve. Subjects were excluded if they were on any prescription medications, pregnant, or had known cardiovascular, hepatic, or endocrine diseases. Prior to recruitment, approval from the local institutional review board was obtained and patients provided written informed consent.

Patients were enrolled Monday–Friday in a research

Results

Fourteen subjects were recruited (mean age 28.6 years; range 15), and twelve (86%) were male. All subjects completed the protocol with no adverse events. Systolic blood pressures (baseline = 132, ± 7.83; PC = 151, ± 11.21; P = .001) (Table 1). QTc intervals (baseline = 423, ± 22.74; PC = 503, ± 24.56; P < .001) (Table 2); magnesium levels (baseline 2.04, ± 0.09; PC = 2.13, ± 0.15; P = .05); and calcium levels (baseline = 9.31, ± .28; PC = 9.52, ± .22; P = .018) significantly increased from baseline (Table 3). While

Discussion

Energy drinks contain added caffeine and other supplements that provide additional amounts of caffeine and other nervous system stimulating properties. Caffeine is a central nervous system stimulant routinely consumed as coffee or tea. When consumed in high doses, this chemical becomes toxic and can result in seizures and even death [16], [17], [18]. Besides added caffeine, another supplement added to many energy drinks is Panax ginseng purported to improve alertness and memory. Several studies

Conclusions

This study in healthy subjects demonstrates that energy drink consumption alters repolarization of the cardiac cycle possibly predisposing consumers to aLQTS, increased blood pressure, and electrolyte alterations. Because these physiological responses can lead to arrhythmias and other abnormal cardiac responses, it becomes important that emergency room personnel assess for energy drink toxicity and recognize these potential life-threatening consequences. Additional studies with larger samples

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      No robust conclusions can be drawn for higher acute intakes (more than 1 L ED), for children and adolescents and for chronic consumption, since there are no data available. ED consumption of 1 L resulted in significant prolongations of the QTc interval in three out of the four studies analyzing this endpoint in adults (Basrai et al., 2019; Kozik et al., 2016; Shah et al., 2016c), an effect which was not observed with moderate ED drinking. One study, which was conducted in the USA, observed enhanced QTc intervals in healthy young adults, which can be defined as serious (Kozik et al., 2016) and could therefore represent a potential health risk.

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    Research activities were performed at Dignity Health-St. Joseph's Medical Center, Stockton CA

    ☆☆

    This was a non-funded study. No authors have any conflicts of interest to report.

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