Energy drinks may increase blood pressure, disturb heart rhythm

Researchers analyzed data from seven previously published observational and interventional studies to determine how consuming energy drinks might impact heart health.

In the first part of the pooled analysis, the researchers examined the QT interval of 93 people who had just consumed one to three cans of energy drinks. They found that the QT interval was 10 milliseconds longer for those who had consumed the energy drinks. The QT interval describes a segment of the heart's rhythm on an electrocardiogram; when prolonged, it can cause serious irregular heartbeats or sudden cardiac death.

"Doctors are generally concerned if patients experience an additional 30 milliseconds in their QT interval from baseline," said Sachin A. Shah, Pharm.D., lead author and assistant professor at University of the Pacific in Stockton, Calif.

"QT prolongation is associated with life-threatening arrhythmias. The finding that energy drinks could prolong the QT, in light of the reports of sudden cardiac death, warrants further investigation." said Ian Riddock, M.D., a co-author and director of preventive cardiology at the David Grant Medical Center, Travis Air Force Base, Calif.

Researchers also found that the systolic blood pressure, the top number in a blood pressure reading, increased an average of 3.5 points in a pool of 132 participants.

"The correlation between energy drinks and increased systolic blood pressure is convincing and concerning, and more studies are needed to assess the impact on the heart rhythm." Shah said. "Patients with high blood pressures or long QT syndrome should use caution and judgment before consuming an energy drink.

"Since energy drinks also contain caffeine, people who do not normally drink much caffeine might have an exaggerated increase in blood pressure."

The pooled studies included healthy, young patients 18-45 years old. "People with health concerns or those who are older might have more heart-related side effects from energy drinks," said Shah.