WHY are energy drinks suspected as a cause for heart attacks in some people?

Don’t assume it’s the caffeine. How often do you hear of people dropping from heart attacks because they drink five cups of coffee a day?

But something else is going on when it comes to energy drinks and a heart attack.

The QT Interval

There is something called a QT interval on an EKG (the test that prints out your heart rhythm).

The QT interval is corrected by a formula to correspond to the heart rate at the time of the EKG. This is called the QTc.

There is a normal range for the QTc, and it’s calculated in milliseconds.

A QTc longer than this millisecond range will get a doctor’s attention — depending on the patient’s medical history, symptoms and medication usage — because QT prolongation can mean a higher risk of sudden cardiac arrest.

But a QTc outside the normal range can also mean operator error (the nurse putting on the EKG leads) and computer miscalculation from the EKG.

Other factors must be considered when noting a prolonged QT interval, such as personal history of fainting episodes.

Energy Drinks May Prolong the QT Interval

A prolonged QT interval means a highter QTc value. For some people this means a higher risk of sudden cardiac death, which may appear as a heart attack.

Why Energy Drinks Cause Apparent Heart Attacks

In one investigation (Shah et al), researchers took a look at the QT interval of 93 healthy people after they drank one to three cans of an energy drink.

An EKG showed that their QT intervals were 10 milliseconds longer than the limit for the normal range.

Now you may be thinking, “Only 10 milliseconds? How can that make a difference?”

Well, it does. Milliseconds count when it comes to how well the heart recharges for its next beat.

If it takes too long (again, measured in milliseconds), this heightens a person’s risk of ventricular fibrillation leading to cardiac arrest.

This isn’t a heart attack per se, but rather, the quivering instead of beating of cardiac muscle, making it impossible to pump blood throughout the body.

In general, a cardiologist becomes concerned when there’s an extra 30 milliseconds to the QT interval from baseline.

The Shah et al study showed that energy drinks can prolong QT interval.

There is a genetic form of this condition, called genetic long QT syndrome.

But even if the prolonged QT interval is caused by an extraneous agent, such as an energy drink, this anomaly is just as serious a concern and has the potential to cause heart problems.

The study also notes that energy drinks increase blood pressure, which certainly isn’t good for the heart.

Stay Away from Energy Drinks

A beverage with carbohydrates will provide you with energy. If you’re growing fatigued during sport or training, drink some regular juice or have a banana, peach or apple.

A so-called “energy” boosting drink is not necessary, even though these are marketed to athletes.

“Certain energy drinks can increase the heart rate significantly because they are stimulants,” says Yaser Elnahar, MD, a cardiologist with Hunterdon Cardiovascular Associates in NJ.

“If you have an excessive amount of stimulants, they can cause rapid heartbeat or even arrhythmias.

“There have been case reports of excessive energy drinks and heart attack — in which the researchers felt the excess intake led to low blood flow and clotting that led to a heart attack.

“There aren’t trials showing energy drinks cause heart attacks directly.”

Dr. Elnahar has publications in the Journal of Atrial Fibrillation, the Journal of Clinical Medicine and Research, Reports in Medical Imaging, and more.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  
Top image: Shutterstock/Yuttana Jaowattanawhy
Source: sciencedaily.com/releases/2013/03/130321205524.htm