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Investigators from multiple institutions conducted a randomized, double-blind, placebo-controlled crossover trial to assess the effect of energy drink consumption on blood pressure (BP) and cardiac conduction. Adults aged 18–40 were eligible if they (a) avoided caffeine and energy drinks for 48 hours before each study visit, (b) had no known medical condition, (c) were nonsmokers, (d) were not pregnant or breastfeeding, (e) were not taking a long-term medication or over-the-counter medication except for oral contraceptives, and (f) were not hypertensive (>140/90 mm Hg) or did not have a prolonged corrected QT (QTc) interval (>450 ms). Demographics were collected at baseline.
Participants completed 3 interventions in a randomized order on 3 separate days with a minimum 6-day washout period in between: drinking 2 16-oz bottles within a 60-minute period of (a) Brand A energy drink, (b) Brand B energy drink, and (c) placebo. Brand A and Brand B were commercially available and contained 304–320 mg/32 fl oz of caffeine with some differences in other ingredients like carnitine and guarana. The placebo drink was carbonated water, lime juice, and cherry flavoring. All drinks were identically packaged, with both participants and study staff blinded to their contents. BP and a 12-lead ECG were obtained from participants at 30-minute intervals for 4 hours on each study day.
The primary outcome was QTc interval, as calculated with the Bazett (QTcB) and Fridericia (QTcF) formulas. Secondary outcomes included systolic BP (SBP) and diastolic BP (DBP). An intention-to-treat analysis was performed, with the maximum value for each outcome analyzed using analysis of variance to assess for differences among the 3 interventions.
There were 34 participants included in analysis, with a mean age of 22.1 years. The maximum SBP, DBP, and QTc values were significantly different with intervention versus placebo drinks. The maximum average change in SBP was 15.9 mm Hg with Brand A, 14.4 mm Hg with Brand B, and 9.8 mm Hg with placebo (P<.001). The maximum average change in QTcB and QTcF intervals was 17.9 and 15 ms for Brand A, 19.6 and 15.2 ms for Brand B, and 11.9 and 6.9 ms for placebo, respectively (P=.005 for QTcB and P<.001 for QTcF). There was no difference in QTc or BP outcomes between Brand A and Brand B.
The authors conclude that energy drinks increase blood pressure and prolong the QTc interval.
Dr Spar has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.
Energy drinks are products that are meant to increase energy and enhance alertness and physical performance. One-third of...
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