For many people, when it comes to energy drinks, nothing works for them other than a steaming cup of black coffee. It is known to inject energy and may wash away your fatigue instantly. But then that's coffee, there are many energy drinks that are known to provide same effect. Moreover, there are many store-bought energy drinks available that "promise" to keep you energised and keep you active throughout the day. These energy drinks may get you all pepped up; however, having them too much may increase your blood pressure levels and the risk of electrical disturbances in the heart, finds a recent study published in the Journal of the American Heart Association.
As per the researchers, having 32 ounces of an energy drink in small interval may shoot our blood pressure levels and may cause disturbances in the heart, further affecting heart rhythm. For the study, researchers examined 34 healthy participants, between the ages of 18 and 40 years. These participants were asked to drink 32 ounces of one of two commercially available caffeinated energy drinks on three different days, within a 60-minute period but no faster than one 16-ounce bottle in 30 minutes each day. Researchers measured the electrical activity of the volunteers' hearts by electrocardiogram, which records the way a heart is beating. They also recorded the participants' blood pressure. All measurements were taken at the study's start and every 30 minutes for 4 hours after drink consumption. Both energy beverages tested contained 304 to 320 milligrams of caffeine per 32 fluid ounces. Caffeine at doses under 400 milligrams is not expected to induce any electrocardiographic changes.
There were a few common ingredients found in the energy drinks like taurine (an amino acid), glucuronolactone (found in plants and connective tissues) and B-vitamins. The placebo drink contained carbonated water, lime juice, and cherry flavouring.
The participants who consumed either type of energy drink, researchers found that the QT interval was 6 milliseconds or 7.7 milliseconds higher at 4 hours compared to placebo drinkers. The QT interval is a measurement of the time it takes ventricles in the heart (the lower chambers) to prepare to generate a beat again. If this time interval is either too short or too long, it can cause the heart to beat abnormally. The resulting arrhythmia can be life-threatening.
The researchers found that the QT interval changes generally continued for four-hour monitoring period rather than being a short-lasting effect after consuming 32-ounces of energy drink. Moreover, there was a statistically significant 4 to 5 mm Hg increase in systolic and diastolic blood pressure in participants who consumed the energy drinks.
"We found an association between consuming energy drinks and changes in QT intervals and blood pressure that cannot be attributed to caffeine. We urgently need to investigate the particular ingredient or combination of ingredients in different types of energy drinks that might explain the findings seen in our clinical trial," said lead author Sachin A. Shah, Pharm.D., professor of pharmacy practice at University of the Pacific, Thomas J. Long School of Pharmacy and Health Sciences in Stockton, California.