Consumption of energy drinks may increase heart disease chances

Energy drinks also have a high sugar content and may contain other plant-based stimulants that produce side effects comparable to those of caffeine.

A single can of an energy drink packs quite a wallop, causing potentially worrisome spikes in blood pressure and in a stress hormone that’s a cousin to adrenaline, say researchers at the Mayo Clinic. Each person drank one 16-ounce can of Rockstar Punched or the sham drink in random order on two separate days.

Just one energy drink can cause potentially harmful spikes in both stress hormone levels and blood pressure in young, healthy adults, a new study shows.

In the study, the researchers had 25 healthy men and women drink a 16-ounce Rockstar energy drink on one day, and a placebo drink on another day.

TIME reached out to the American Beverage Association for comment. Participants were fasting and abstained from caffeine and alcohol 24 hours prior to each study day.

Caffeine levels remained unchanged after the placebo drink, but increased significantly after energy drink consumption. They simultaneously tested a placebo that looked and tasted similar but lacked the caffeine and stimulants such as taurine and milk thistle extract found in the energy drink, the researchers report in a press release. “We now show that the increases in blood pressure are accompanied by increases in norepinephrine, a stress hormone chemical, and this could predispose an increased risk of cardiac events – even in healthy people”.

Researchers found that in addition to increases in blood pressure after consuming the energy drink, participants’ norepinephrine levels increased more than twice as much when compared to those who drank the sham drink. Norepinephrine levels increased 73.6% after drinking the energy drink compared to 30.9% after drinking the placebo beverage.

The team underlined that there were limitations in this pilot study mainly due to the small sample size and the only 1 energy drink being studied.

They conclude that further studies are warranted to determine whether the changes in blood pressure and norepinephrine identified are likely to increase cardiovascular risk.