This may be sobering news to some bar patrons, but a study out Tuesday suggests that mixing alcohol with an energy drink may not prolong that alcoholic “buzz.”

The findings throw cold water on the popular notion that energy drinks, such as Red Bull, counter the depressive effects that follow the initial stimulation produced by alcohol.

The drinks typically consist of carbohydrates, B vitamins, caffeine and taurine, a derivative of an amino acid found in animal tissue.

Some studies have shown that the beverages, or their main ingredients, may improve mood and physical performance, but there’s been little research into their effects when mixed with alcohol.

The new study involved 14 healthy men whose prowess on the stationary bike was tested after they drank either water, vodka, Red Bull or a mixture of vodka and Red Bull.

Researchers found that the men’s cycling performance one hour after having the mixed drink was similar to their performance after alcohol alone.

Dr. Maria Lucia O. Souza Formigoni and her colleagues at the University of Sao Paulo in Brazil report the findings in the journal Alcoholism: Clinical & Experimental Research.

The study suggests that using an energy drink as a mixer will not change a person’s physical functioning, said Dr. Maristela G. Monteiro of the Pan American Health Organization in Washington, D.C.

However, whether the drink combination makes people feel more invigorated is another question, added Monteiro, who was not involved with the research.

If people “feel better” when they mix their alcohol with an energy drink, she said, then the concern is that they’ll feel free to drink more than unusual or perhaps drive a car.

In this study, Monteiro pointed out, the addition of the energy drink did not alter participants’ blood alcohol levels or certain other physiological effects of drinking.

“It’s not changing the basic effects of alcohol,” she said.

In a statement, Formigoni said that prior to this study, she and her colleagues surveyed energy drink enthusiasts at Brazilian nightclubs. Of 136 people, 76 percent said they mixed their energy drinks with alcohol, citing such effects as “happiness,” “euphoria,” and invigoration.

According to the researchers, such purported benefits may merely reflect a “placebo effect” - more to do with expectations than physiology. Still, they add, given the popularity of the mixed drinks, further study is needed.

SOURCE: Alcoholism: Clinical & Experimental Research, September 2004.