CHICAGO -- As part of her marathon training, Daisy Carranza has taken an over-the-counter pain reliever nearly every day for the last several months.
On race day, she's prepared to pop at least seven Extra Strength Tylenol capsules: two at the starting line, three at mile 18 -- just before the body starts to rebel -- and two at the post-race party, to help with recovery.
"It's a regular thing," said Carranza, 31, of Chicago, who is entered in her fourth Bank of America Chicago Marathon. "I have a lot of knee, back and shoulder pain, so I look at Tylenol in the same way as protein bars and Gatorade."
Like lucky caps and favorite shoes, marathoners often rely on over-the-counter pain relievers to get them through both the endless training and the grueling 26.2-mile race itself. The most popular drugs generally contain acetaminophen -- the active ingredient in Carranza's Tylenol -- or ibuprofen, part of a class of medications called NSAIDs, or non-steroidal anti-inflammatory drugs.
The medications can be a godsend when taken as directed: for headaches, fevers or acute injuries, such as a twisted ankle. But both ibuprofen and acetaminophen pose well-documented health risks, especially when they're consumed in large amounts or for an extended time.
There's also little evidence to suggest that athletes receive any benefit from taking pain relievers before a race. And emerging research is starting to show that ibuprofen can actually cause inflammation under certain conditions and may interfere with the body's processes of recovery and adaptation.
"We fall into the assumption that anything available over the counter is safe and that we know how to use it," said Wendy Kohrt, a professor of medicine at the University of Colorado Anschutz Medical Campus who has studied NSAIDs' effects on bone formation. "But it's just not true."
When taken preventively, pain relievers "have the potential to reduce how well your tissues adapt to the exercise," said Stuart Warden, an associate professor in the Indiana University School of Health and Rehabilitation. "We all know exercise makes muscles bigger, bones stronger and tissues adapt, changing in structure," he said. "NSAIDs block a pathway that's important for that adaptation."
Athletes in all sports and at all levels swear by over-the-counter painkillers, especially ibuprofen, which is known by its fans as "Vitamin I." A 2008 survey of participants in an Ironman triathlon in Brazil found that almost 60 percent reported using NSAIDs in the three months leading up to the event, according to a study in the British Journal of Sports Medicine. Almost half reported taking pills during the race.
Another report that looked at medication use by male soccer players competing in the 2002 and 2006 World Cups called the high intake of NSAIDs "alarming."