Dutch researchers say they've found that a can of Red Bull does wonders for driving ability over long hauls, reducing fatigue while improving performance in everything from steering straight to maintaining a steady speed.
Testing volunteers in a driving simulator, they found the gap in skill between those who drank the energy product and those who didn't was as much as if the latter group had consumed enough alcohol to be over the legal limit — a blood alcohol content of 0.05 percent — in much of Europe.
Drowsy driving is linked to more than 100,000 auto accidents each year in the United States, resulting in some 40,000 injuries and at least 1,500 deaths, according to the National Highway Traffic Safety Administration.
"The improvement caused by Red Bull on driving performing and reducing sleepiness lasted for the whole two hours of the test," said Joris Verster of Utrecht University, whose findings appear in the journal Psychopharmacology.
He added that, based on previous research, the effects of Red Bull seem stronger than those of coffee ounce-for-ounce, but that any energy drink with the same combination and amounts of "functional" ingredients ought to improve driving skill.
A 250 mL can of Red Bull costs a few dollars and contains 80 mg of caffeine, which gives it roughly the same kick as a regular cup of coffee. Other ingredients include loads of sugar, the amino acid taurine, whose effects on alertness aren't clear, glucuronolactone, touted as a detoxifying agent, and various B vitamins.
The Austrian beverage maker, which sponsored the new study, claims sales of four billion cans a year worldwide. Consumers in the United States have a particular thirst for the energy drinks, downing an average of three liters (about 0.8 gallons) annually, according to Mintel, a market research firm.
Verster's group studied the effects of Red Bull on 24 men and women taking a simulated four-hour car trip. Although the participants never ventured out on the road, Verster said the driving simulator reflected the chances of getting involved in a real traffic accident.
After two hours, some of the drivers took a 15-minute break during which half drank 250-mL cans of Red Bull and the rest drank sham cans that tasted like Red Bull but were missing the key ingredients (although not the sugar). They then got back in the simulator and "drove" for another two hours. A third group of volunteers drove for four hours with no breaks or drinks.
Volunteers in all three groups performed equally well in the simulator for the first two hours. But after the break, those who drank Red Bull performed markedly better than the others. They also reported feeling more alert in the second half of the test and rated their driving skills more highly.
But Dr. John P. Higgins, a sports cardiologist at the University of Texas Medical School at Houston, cautioned against using the products. Just last week, he published a report raising concern about the ingredients in common energy drinks (see Reuters Health story of November 12).
For starters, Higgins said, the drinks are unregulated, poorly studied and even in healthy people have been linked to heart attacks, seizures and other potentially fatal conditions.
Norway, Denmark and France banned Red Bull after a study showed "rats that were fed taurine exhibited bizarre behavior, including anxiety and self-mutilation."
What's more, researchers have found that people who consume energy drinks are more likely to engage in risky behaviors, such as smoking marijuana, drinking heavily -- and driving without a seatbelt.
Many combine the drinks with alcohol, which blunts any beneficial effect that the stimulant beverages might have on driving skill, Higgins said. And some energy drinks, such as the controversial Four Loko, already hold alcohol.
"People have one, and because of the stimulant effect, they're feeling like they haven't had any alcohol," Higgins said. "The bad news is, the alcohol is still having its effect. The alcohol is suppressing their ability to see something and react, even though in their mind they think they're faster and quicker."