Once upon a time, people in need of an energy boost drank tea or coffee. Then came caffeinated soft drinks like Coke, Pepsi and Mountain Dew. Now, there are energy drinks like Java Water, Krank 20, Rockstar, XTC Power Drink, Red Bull, Bawls, Monster Energy, Whoop-Ass, Pimp Juice, Venom, Adrenaline Rush, Water Joe, Buzz Water and Afri-Cola.

As life in the United States moves at an ever-faster pace, people seem to be turning to caffeine and other stimulants to help them keep up. The new energy drinks are especially popular with college students, shift workers, and video and computer-game players.

These bottled or canned energy drinks each have a little less caffeine than a shot of espresso or a strong cup of coffee, but twice as much as the average cola drink. Most of them contain plenty of sugar, and about 130 calories; some diet versions without sugar are available.

Many of the energy drinks on the market get their caffeine from the guarana plant, rather than from coffee beans. Some contain an amino acid called taurine, which manufacturers claim enhances the effects of caffeine. Some also contain vitamins and herbal supplements such as gingko biloba and ginseng, with unsubstantiated claims of healthful benefits.

There is no doubt that energy drinks provide a burst of energy. Caffeine in any form is a central nervous system stimulant and increases cardiac output, so it temporarily improves mental and physical performance. It also improves mood for some people.

The drawbacks to energy drinks outweigh any benefits for some people. Anyone with heart problems – such as arrhythmias, palpitations and high blood pressure – should avoid these drinks due to the stimulant effects on the heart. Also, anyone who suffers from panic attacks or anxiety problems should not consume energy drinks, as they often aggravate these problems.

Those with kidney disease, heartburn (esophageal reflux) or insomnia should avoid energy drinks, as should anyone taking antidepressant medication. Caffeine can also worsen premenstrual symptoms such as irritability and breast tenderness in some women.

Even people with no health problems can experience bad side effects from energy drinks. Each person has a different tolerance for caffeine; those who are less tolerant of caffeine’s effects may feel nervous, irritable or sleepless. Some can feel their heart pounding; others develop nausea, a stomachache, hand tremors or an inability to concentrate.

With high doses of caffeine in any form, the body becomes tolerant to caffeine’s effects and requires more and more over time to get the same buzz.

The greatest danger with energy drinks is the newly popular ritual of mixing them with alcohol, or drinking them before going out and drinking alcohol. The mix of caffeine and alcohol creates a false sense of being alert and sober.

This mixture of a stimulant (caffeine) and a depressant (alcohol) can lead to serious consequences such as dehydration, vomiting and in extreme cases, heart failure.

Like many drugs, caffeine and alcohol are relatively safe in low doses. But if a typical college student goes out and consumes five or six drinks made with Red Bull and vodka in the space of a few hours, he or she will exceed the safe doses of these drugs. Loss of inhibition, aggressive behavior and loss of the ability to make good judgments can lead to unwanted sexual activity, date rape, fights, drunken driving and blackouts.

Advertisements for energy drinks are heavily marketed to people under 30, and they are increasingly popular with teenagers. Parents who don’t let their children drink coffee may be unaware that energy drinks contain significant amounts of caffeine.

Kathryn B. Brown is a family nurse practitioner with a master’s degree in nursing from OHSU. Is there a health topic you would like to read about? Send ideas to kbbrown@eastoregonian.com.