5 hours of energy is a placebo

Energy drinks can give "angel wings"

STOCKTON. In addition to an increase in blood pressure, US researchers at the University of the Pacific in California have now proven another dangerous effect of energy drinks. In a study with test persons, the consumption extended the QT interval by several milliseconds (JAHA 2019; online June 4).

Energy drinks contain taurine, inositol, glucuronolactone, vitamins and lots of caffeine. The researchers examined the cardiovascular effects of two commercially available products in the randomized, placebo-controlled cross-over study.

34 healthy subjects (18 to 40 years old) drank 946 milliliters (32 fl.oz.) of one of these two drinks or of a placebo drink (water with lime juice and cherry flavor) in one hour. After a six-day break (“wash-out”), a change was made until each subject had drunk each of the three variants. The energy drinks contained 304 or 320 mg of caffeine.

Electrical activity of the heart measured

In addition to blood pressure, an EKG was also used to measure the electrical activity of the heart, before and after consuming the drinks and every 30 minutes for four hours. The primary endpoint was the QT interval, reports Professor Sachin A. Shah's team.

Result: The QT interval after consuming the energy drink was 6.0 or 7.7 milliseconds longer than after consuming the placebo drink, depending on the product. The QT interval is known to be the time between the beginning of the QRS complex and the end of the T wave. The de- and repolarization of the heart chambers fall within this interval.

If the period is too short or too long, it can lead to life-threatening torsade de pointes arrhythmias.

Parallel to the prolongation of the QT time, the systolic and diastolic blood pressure increased by an average of 4.0 to 5.0 mmHg after energy drink consumption. Caffeine is probably not the cause of these effects, emphasize the researchers.

The amounts of caffeine consumed were not exorbitantly high - daily rations of up to 400 mg are considered harmless. The authors of the study therefore assume that a different ingredient or a combination of several are the cause of the changed QT intervals and the rise in blood pressure.

High consumption is a cause for concern

The researchers find the high consumption of energy drinks questionable. In the US, it is estimated that one in three US teenagers between the ages of 12 and 17 regularly drinks such drinks. A lot of them have to be treated in emergency rooms and there are a few deaths.

The researchers point out that the drinks are often consumed in combination with alcohol or other drugs or in the event of health disorders. Energy drinks should be discouraged if you have high blood pressure or long QT syndrome. Page 2

Please also read the guest commentary by Professor Stephan Martin:Energy drinks: dubious facts are hidden

Further information on cardiology can be found at www.kardiologie.org