The fine print on the aluminum cylinder's side struck Keith Wiedenfeld as funny, but he heeded Monster Energy's request nonetheless.
"Consume responsibly – limit 3 cans per day," reads the black can displaying Monster's signature tattered, neon-green "M."
Wiedenfeld, a freshman at McHenry County College, would grab a Monster and a Snickers bar each day before his lunchtime shift in the Culver's kitchen. That was all he needed until, he said, the effect dulled. Wiedenfeld switched to Rockstar, but that just made him anxious and jittery.
So he backed off the stuff altogether – a decision a small but growing number of people across the country are facing. From 2007 to 2011, emergency department visits related to energy drinks increased from 10,068 to 20,783, according to a survey by the Substance Abuse and Mental Health Services Administration. The number of visits for the same reason was below 1,500 in 2005.
Emergency physician Dr. Mark Thompson of Advocate Good Shepherd Hospital said the drinks can present patients with symptoms such as a rapid heartbeat and chest discomfort, and feelings of anxiety.
Emergency room cases have been rare, Thompson said, but they are becoming more frequent.
"If you want to drink a Red Bull now and then, and you're otherwise healthy, I think that's fine," Thompson said. "I don't think that kids should be drinking them. I don't think you should be drinking multiple in a day."
The Food and Drug Administration said late last year that it is continuing to investigate energy drinks after reports of a handful of deaths, in addition to other illness and injury. The parents of a 14-year-old Maryland girl who died in late 2011 after consuming 48 ounces of Monster are suing the California-based company.
Closer to home, the Chicago City Council could consider enacting the first U.S. ban on energy drinks. A proposal from Alderman Ed Burke would prohibit the sale of drinks that contain at least 180 milligrams of caffeine in addition to additives typically found in energy drinks, such as taurine or guarana.
Although the figures aren't advertised on all cans, a Consumer Reports study recently found that most popular energy drinks pack between 160 and 420 milligrams per 16 ounces. A 16-ounce cup of Caribou Coffee's daily brew contains 305 milligrams of caffeine.
But any mounting health concerns around the energy boosters have yet to curb the still-growing market.
Energy drink consumption started growing strongly about a decade ago, and then hit a speed bump during the recession, Beverage Digest Editor John Sicher said. While other soda products continued to see a slow, steady decline, energy drinks once again took off. The market grew by about 16 percent in 2011, and Sicher expects 2012 growth to come in between 12 percent and 15 percent when numbers are finalized.
Energy shots such as 5-hour Energy – which aren't tracked by Beverage Digest – grew by 168 percent between 2008 and 2012, according to the trade publication Prepared Foods.
Sicher said energy drink numbers have leveled off in recent months, around the same time energy drink companies have dealt with press highlighting their products' potentially detrimental health effects. But Sicher doesn't see a correlation.
"It's gotten to a fairly large size," he said of the energy drink market. "Household penetration is not increasing."
Wiedenfeld, of Huntley, hasn't given up energy drinks completely. He'll pick one up on his way to work if he was up late the previous night. Mainly, though, he gets by on Mountain Dew, a change he's made somewhat reluctantly.
"Energy drinks kick in a lot faster," Wiedenfeld said.
Wiedenfeld's views on the high-caffeine drinks differ greatly from his friend Austin Burbank, of Lake in the Hills, who sat across from him in the commons area in MCC's Building B on a recent Wednesday. Though it was lunchtime, the two had only their opened laptops in front of them.
Burbank admits he needs less energy than the average person as it is – he sleeps about four hours a night, he said – but he doesn't understand the energy drink craze. He has concerns that there isn't enough known about them. And he's never tried one.
"I never have. I never will," said Burbank, also a freshman at MCC. "To me, it's just stupid to drink something that will energize you so much."