Drinking more than two energy drinks per day may make you peppy, but could also stress your heart.

That’s the latest warning from researchers who say drinking more than just two of the heavily-caffeinated drinks is associated with serious heart problems, including palpitations, a raised heart rate, and chest pain.

In a study published in International Journal of Cardiology, Australia researchers who surveyed patients, aged 13-40, hospitalized with heart patients found 70 percent had previously consumed some sort of energy drink, Medical Xpress reports.

University of Adelaide's Dr. Scott Willoughby said the study found a direct link between energy drink consumption and hospital admissions for adverse heart reactions.

"Of the patients surveyed, 36 percent had consumed at least one energy drink in the 24 hours prior to presenting at the hospital and 70 percent had consumed some sort of energy drink in their lifetime," Dr. Willoughby said.

"Eight of these patients had consumed a large quantity (more than five drinks), with one patient having consumed 12 energy drinks with alcohol. Those patients who were heavy consumers of energy drinks were found to have a significantly higher frequency of heart palpitations than those who consumed less than one per day.

"And, importantly, fast heartbeat, heart palpitations and chest pain was seen in energy drink consumers who were healthy and had no risk factors for heart disease."
The patients were surveyed at Lyell McEwin Hospital in South Australia in 2014 and 2015.

"Energy drinks have become enormously popular in the past decade and half are consumed extensively by people who wish to reduce fatigue, increase wakefulness, and improve concentration and performance," noted Dr. Ian Musgrave, from the University of Adelaide's Discipline of Pharmacology.

"Different brands of energy drinks contain different ingredients, but most of them combine high levels of caffeine with large quantities of sugar as well as vitamins and herbal extracts. Caffeine is one of the safest stimulants we know about but it looks like caffeinated drinks are more problematic for people with pre-disposed heart conditions than they are for normal people.

"People are unlikely to slam down seven espressos one after the other but people are more likely to — especially under the influence — misuse energy drinks in that way."

Dr. Musgrave added that the study shows some people may have a genetic pre-disposition to irregular heartbeats that may not be apparent until they had been stimulated with caffeine.