Energy drinks could be giving your heart the jolt it needs to get through the rest of the day. It is possible that you are one of those who at two in the afternoon begins to decline and still has to go to train after work. Drinking these types of beverages can help your fatigue disappear and make you feel like a whole new person again, right? Well, you should be careful. Energy drinks are full of caffeine and "natural" additives, which several studies recognize as dangerous for health.
Now, new research, published in the Journal of the American Heart Association, suggests that caffeinated energy drinks might increase blood pressure and even temporarily alter your heart's electrical system.
How do energy drinks influence the QT interval?
The researchers recruited 34 healthy people, aged between 18 and 40, and separated them into two groups: one that consumed commercially available energy drinks with between 304 and 320 milligrams (mg) of caffeine; and another group that drank a placebo beverage of carbonated water, lime juice, and cherry flavorings.
The participants drank about 100 centiliters of one of these beverages on three separate days. The researchers measured the electrical activity and blood pressure of their hearts. Measurements were taken before consumption, twice during the hour they drank the beverage, and four hours after consumption.
Compared to the placebo group, the volunteers who drank the energy drink showed longer QT intervals . These intervals are the time it takes for the lower chambers of your heart to prepare for a heartbeat, sometimes up to four hours later. This is an important factor because if the interval is too short or too long, it can cause arrhythmia and make the heart beat abnormally.
QT interval sample
Additionally, those in the energy drink group had a significant increase in systolic and diastolic blood pressure, the researchers found. The average was a 4 to 6 millimeters of mercury (mmHg) rise in systolic pressure (the top of your reading) and 6 mmHg for diastolic (the bottom number).
A normal blood pressure is 120/80 mmHg. In other words, to consider high blood pressure, it should go up to 129/81 or more; and it's something that might seem possible with a couple of energy drinks.
Could caffeine be to blame for these symptoms?
Although the study has some limitations (because the sample size is somewhat small and the ingredients may vary), the researchers suggested that caffeine is not the culprit behind these effects. However, they still don't know what role caffeine plays when combined with common ingredients such as amino acids, sugar, B vitamins, and guarana.
You might think the effects are temporary and that you won't have any heart problems, but the reality is that you should avoid consuming large amounts, especially in a short period of time. You should also pay special attention if you have heart problems or are taking any medication. This is especially true for people with underlying long QT syndrome, hypertension, or those taking medications such as antiarrhythmics and antibiotics.