Energy drinks, which have been linked to deaths and hospitalizations, may boost blood pressure and lead to an erratic heartbeat, a study found.

An analysis of seven previous studies showed the beverages appeared to disturb the heart's natural rhythm, which over time may lead to an irregular heartbeat or death and raise blood pressure.

The U.S. Food and Drug Administration and other regulators have been investigating the drinks made by companies including Monster Beverage Corp (MNST)., Living Essentials LLC (0194689D) and Red Bull GmbH after they were linked to hospitalizations and death. Today's findings mean people, particularly those with pre-existing heart conditions, should be cautious when consuming the drinks, said Sachin Shah, the lead study author.

"We need to look at the effects of long-term energy drinks consumption and see what the consequences are," said Shah, an assistant professor of pharmacy practice at the University of the Pacific in Stockton, California, in a telephone interview. "Everything is good in moderation. Drink them within the limits that have been provided and be vigilant of what else you're consuming with it."

The high caffeine content may be causing these heart changes or it could be another ingredient in the drinks, Shah said. More studies are needed though to look at the ingredients and their health effects, he said. The heart changes don't appear to be permanent, he said.

Today's findings were presented at the American Heart Association meeting in New Orleans.

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