Energy drinks can raise blood pressure and may cause irregular heartbeats, according to a recent study conducted at Travis Air Force Base in California (Journal of the American Heart Association, April 26, 2017;6(5)). This extremely well-planned, -performed and -controlled study shows that two hours after drinking 32 ounces (four cups) of a popular energy drink, some of the healthy volunteers developed irregular heartbeats (corrected QT interval) and elevated systolic blood pressure.
The QT interval on an electrocardiogram is the time it takes the lower heart (ventricles) to recover before the next heartbeat. If it is too short or too long, it can cause irregular heartbeats that can cause sudden death.
The study’s control drink containing just sugar and caffeine did not cause irregular heartbeats, and although it raised blood pressure a little bit, it was far lower than that caused by the name-brand energy drink and returned to normal much faster.
Both types of drink contained the same 108 g of sugar and 320 mg of caffeine, but the energy drink contained various other ingredients that are listed as a “proprietary energy blend.” Those who took the caffeine-only drinks had their blood pressures return to normal after six hours, while those who took the energy drinks had much higher blood pressures at two hours and still had elevated blood pressures at six hours. Diastolic blood pressures and heart rates were the same for both groups.
What You Need to Know about Energy Drinks
- There are more than 500 energy drink products available on the market today, and they are advertised to boost physical and mental alertness.
- This study suggests that components other than sugar and caffeine in the commercial drinks contributed to the increased rate of irregular heartbeats and elevated and prolonged blood pressures.
- The FDA has already withdrawn the ingredients ephedra and cisipride because of their possible association with irregular heartbeats.
- Some research papers associate the components of the “proprietary energy blends,” such as taurine, L carnitine and panax ginseng, with irregular heartbeats, even though they have not been proven to do so. They are added to some energy drinks.
- Caffeine in doses less than 400 mg per day appears to be safe, although extremely rarely it can cause irregular heartbeats in healthy people (Pharmacotherapy, 2001;21:437–442). Doses greater than 400 mg can, on rare occasions, cause irregular heartbeats (Int J Cardiol, 2013;166:e41–e42).
- Many energy drinks have ingredients other than caffeine and sugar that have never been tested for side effects. Most studies claiming that energy drinks are safe were done without adequate control groups, used very low doses, or followed people for too short a time (references 14-19 in J Amer Ht Assoc, April 26, 2017;6(5)).
- Earlier studies have also associated irregular heartbeats with commercial energy drinks (Int J Cardiol, 2016;218:318–323).
People who are most likely to suffer from irregular heartbeats from stimulants in energy drinks include those who (already) have irregular heartbeats, high blood sugar levels, low potassium or magnesium blood levels, or who are obese (Clin Cardiol, 2009;32:E93–E99), or who have alcohol or illicit drugs in their systems (JAMA, 2013;309:245–246).
In their conclusion, the study authors suggest that ingredients contained in energy drinks other than caffeine warrant further investigation. Meanwhile, I recommend that if you decide to use energy drinks, read the label and pick the ones that have the lowest number of ingredients beyond caffeine and sugar.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.