Most people down energy drinks if they want an extra boost. Yet that extra energy boost may translate into small boosts in blood pressure too.
A recent study presented at a conference on heart health looked at the effects of energy drinks on individuals.
The researchers found a small increase in participants' systolic blood pressure and another heart health marker after drinking energy drinks.
However, it's not clear what these increases mean or whether they are reason for concern.
The study, led by Sachin A. Shah, PharmD, of the University of the Pacific in Stockton, California, involved searching for all studies in medical research databases related to energy drinks and cardiovascular effects.
The researchers included any clinical studies in which the authors reported on the effects of an energy drink on participants' blood pressure, heart rate and QT intervals.
The QT interval is the time that passes between the activation and relaxation of the two lower chambers of the heart, called the ventricles. Each time one of these chambers contracts, it sends out an electrical signal that can be measured.
QT intervals between these signals are measured in fractions of a second. A longer QT interval than average can indicate potential health issues, increased chances of heart arrhythmias (irregular heartbeats), fainting or other more serious heart events.
Of the 351 studies the researchers found, seven that met their criteria were included. These seven studies included a total of 93 participants who had data on QT intervals and 132 participants who had data on systolic blood pressure (the top number in a blood pressure reading). All the participants were between 18 and 45 years old.
The researchers analyzed all the data together from these studies. They found that participants' QT interval was extended by an average of 10 milliseconds after drinking energy drinks compared to the QT interval before consumption of the energy drinks.
“Doctors are generally concerned if patients experience an additional 30 milliseconds in their QT interval from baseline,” said Dr. Shah in a prepared statement.
The researchers found that the systolic blood pressure of participants increased an average 3.5 mmHg after having the energy drinks, compared to before.
Additionally, it is important to note that energy drinks contain caffeine. It is possible that caffeine derived from any source, such as coffee or soft drinks, may have the same effects on the QT interval or systolic blood pressure.
The researchers did not study or report on the effects of caffeine from any source.
The researchers also did not report how long the higher blood pressure or the longer QT interval lasted, and it's unclear whether these changes might indicate any health concerns.
Basically, these findings mean that researchers must do more study into the effects of energy drinks and caffeine to better understand whether these substances could present potential health risks to individuals, especially those with other heart-related risk factors.
The study has not been published in a peer-reviewed journal where other researchers have been able to review its quality or findings. Therefore, the results should be interpreted cautiously.
The study was presented March 21 at American Heart Association’s Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2013 Scientific Sessions. The authors declared no conflicts of interest. No information was available regarding funding.