People with a certain genetic heart condition may react poorly to energy drinks, Live Science reports.
In small randomized, double-blind study, University of Sydney researchers gave patients with familial long QT syndrome either caffeinated energy drinks or control drinks. Familial long QT syndrome can led to a rapid, irregular heartbeat and sudden death, and affects about one in 2,000 people.
As they report in the International Journal of Cardiology, the researchers found that the patients given the caffeinated energy drinks had increased blood pressure levels and that a portion of patients also had prolonged QT intervals, which could led to dangerously irregular heartbeats
"Some individual patients may be at a higher risk," says senior author Christopher Semsarian in a statement. "We therefore suggest caution in allowing the consumption of energy drinks in young patients with LQTS."
In an editorial also appearing in the International Journal of Cardiology, IRCCS Istituto Auxologico Italiano's Peter Schwartz and Federica Dagradi note that many long QT syndrome patients don't exhibit symptoms until after their teenage years. "[This] implies that a significant number of youngsters with LQTS will help themselves to energy drinks without knowing their real condition and thus endangering themselves," Schwartz says in a statement.