Study: energy drinks, liquor are a bad mix

The University of Florida study finds mixing the two impairs judgment.

Published: Thursday, February 11, 2010 at 6:01 a.m.
Last Modified: Wednesday, February 10, 2010 at 9:39 p.m.

Mixing energy drinks with liquor can be a cocktail for disaster, a new University of Florida study shows.



Energy DrinkServing sizeCaffeine (mg)
Spike Shooter8.4 oz.300/td>
Cocaine8.4 oz.280
Monster Energy16 oz.160
Full Throttle16 oz.144
Rip It, all varieties8 oz.100
Enviga12 oz.100
Tab Energy10.5 oz.95
SoBe No Fear8 oz.83
Red Bull8.3 oz.80
Red Bull Sugarfree8.3 oz.80
Rockstar Energy Drink8 oz.80
SoBe Adrenaline Rush8.3 oz.79
Amp8.4 oz. 74
Glaceau Vitamin Water Energy citrus20 oz. 50
SoBe Essential Energy, berry or orange 8 oz.48
CoffeeServing sizeCaffeine (mg)
Starbucks Grande16 oz. 320
Soft DrinkServing sizeCaffeine (mg)
Vault12 oz.71
Jolt Cola112 oz.72
Mountain Dew MDX12 oz.71
Coke Classic12 oz.35
7-Up or Sprite12 oz.0
-- Center for Science in the Public Interest

There's a $5 billion market for so-called "energy" drinks, and it is fueled largely by college-age consumers - or younger.

With such names as "Monster," "Full Throttle," "Red Bull" and "Rockstar," the caffeine-laden drinks are marketed to appeal to the young.

UF researchers found that college students who choose to party like a rock star at a bar or club by mixing energy drinks with alcohol are putting themselves at real risk.

Mixing alcohol and energy drinks in combinations such as the Jager Bomb (Jagermeister and Red Bull) or Red Bull and vodka isn't just a crime against taste. Doing so can trick the brain into believing you're not as drunk as you are.

In the UF study, appearing in the April issue of the journal Addictive Behaviors, researchers were posted outside popular Gainesville bars and clubs between 10 p.m. and 3 a.m. They asked college-age customers leaving the bars what they had been drinking and did an assessment of their sobriety. The patrons were asked about their drinking history and whether or not they intended to drive that night.

The study was funded by the UF President's Office.

When the data from more than 800 randomly selected bar patrons were compiled, researchers said those who'd been drinking energy drinks mixed with alcohol were three times more likely to leave highly intoxicated and four times more likely to intend to drive than bar patrons who'd been drinking only alcohol.

"Previous laboratory research suggests that when caffeine (a stimulant) is mixed with alcohol, it overcomes the sedating effects of alcohol," said Dennis Thombs, lead researcher and associate professor in the UF College of Public Health and Health Professions' department of behavioral science and community health. "This may lead people to drink more or make uninformed judgments about whether they are safe to drive."

The result is a partier who is "wide awake and drunk," said study co-author Bruce Goldberger, director of toxicology in the UF College of Medicine.

"There's a common misconception that if you drink caffeine with an alcoholic beverage that the stimulant effect of the caffeine counteracts the depressant effect of the alcohol," Goldberger said. "That is not true. We know that caffeine aggravates the degree of intoxication, which can lead to risky behaviors."

Bar patrons who reported drinking alcohol mixed with energy drinks had an average breath-alcohol concentration reading of 0.109, well above the legal driving limit of 0.08. Fueled by energy drink cocktails, they left bars later at night, drank for longer stretches, ingested more grams of ethanol and were four times more likely to say they intended to drive within an hour of leaving the bar.

Another researcher who has studied the combination of alcohol and energy drinks is Dr. Mary Claire O'Brien of the Wake Forest University School of Medicine.

O'Brien says that mixing the caffeine of energy drinks with alcohol is like "getting into a car and stepping on the gas pedal and the brake at the same time."

"Students whose motor skills, visual reaction times and judgment are impaired by alcohol may not perceive that they are intoxicated as readily when they've also ingested a stimulant (caffeine)," O'Brien said. "Only the symptoms of drunkenness are reduced, but not the drunkenness. They can't tell if they're drunk; they can't tell if someone else is drunk. So they get hurt, or they hurt someone else."


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