Socialite Paris Hilton keeps a Red Bull in her designer purse next to her Chihuahua, Tinker Bell.
Locally, at nearly every health club or fitness center, people are bolting down the energy drink du jour before hitting the treadmill, cycle or free weights.
Members of the medical community believe energy drinks are mostly a harmless waste of money, although in some cases they can cause health problems or make existing problems worse.
They may contain caffeine, various B vitamins, amino acids, carbohydrates and herbal extracts from the Amazonian guarana plant or the Chinese ginseng root.
These drinks are different from sports drinks, like Gatorade, Powerade or All Sport, which are formulated with carbohydrates and fluids to rehydrate and replace electrolytes.
"They get you up really fast then drop you fast, so you wind up being even more tired."
He does, however, enjoy a Red Bull when he's relaxing, and usually it's mixed with alcohol.
"If a person is very active and is burning up calories, then replacing them with sugar while exercising makes some sense; but if the person is sedentary, then they're just storing extra calories as fat."
Caffeine in mild doses is probably harmless, but in large doses "can make people shaky and cause potential cardiac problems," Gleeson said.
Caffeine is a weak diuretic, so it is "not the ideal way to replace fluid losses, and in larger amounts, could counteract the fluid you're taking in," Gleeson said.
The American Dietetic Association and the American College of Sports Medicine recommend people drink 6-12 ounces of water for every 15-20 minutes they exercise, said Anne Rabjohn, a registered dietitian at Lovelace Sandia Health Systems.
The caffeine, sugar and host of vitamins, minerals, amino acids and supplements "will not improve their exercise performance," Rabjohn said.