Blisters are the bane of weekend hikers and Olympic marathoners alike. Stanford researchers say they've found a simple, cheap method to help prevent them.
That humble hero is paper surgical tape, which often costs less than a dollar and is sold at most any pharmacy.
Their study, published Monday in the Clinical Journal of Sports Medicine, found that the paper tape reduced the instance of blisters by 40 percent.
Lead author Grant Lipman, an emergency medicine doctor at Stanford Health Care, says he was inspired by years of treating ultramarathoners.
"I started noticing just how trashed people's feet will become. And over 10 years of races, you just see these amazing athletes who have trained for years and spent all this money and they keep telling me the same thing — 'Doc, I feel great, it's just my feet.' And they'd be dropping out, they'd be hurt," Lipman says.
He says that decades of studies on blister prevention have failed to come up with an effective, low-cost solution. But anecdotal evidence suggested paper tape might work, so the team enlisted 128 ultramarathoners for a trial.
Those runners were all participating in RacingThePlanet, a 155-mile, six-stage ultramarathon held in the Jordan, Gobi, Madagascar and Atacama deserts in 2014.
On each runner, the researchers randomly selected a foot. They then asked the runner if that foot had any blister-prone areas. If it did, that part was taped; if not, they taped a randomly selected area.
"Then, we would compare on that just one foot their most sensitive area versus the rest of the foot. And we did that so we could directly see, could this tape prevent a blister directly under the tape?" Lipman says. "We really wanted to nail down the efficacy of the intervention."
According to the study, 98 of the 128 runners did not develop blisters under the tape. At the same time, 81 of the 128 got blisters in untaped areas.
So why does this work so well?
"The paper tape itself is very thin and it's very smooth. We theorized that because it's so smooth, it deceases friction and rubbing and shear stress on those sensitive areas just underneath the tape," Lipman says. He adds: "It's thatshear stress within the cell layers that causes separation of the cells and blister formation."
The paper tape also has a low adhesive quality, so when it does come off, it's less likely tear the skin and leave an open wound, he says.
Much previous research has been conducted seeking to prevent the "enemy of the feet," Lipman adds, but nobody had looked at paper tape specifically until now.
A study published in 1998 tried applying antiperspirant to the feet of military cadets to prevent blisters. The researchers found this to reduce blister formation, but with an unintended consequence — 57 percent of the cadets using the antiperspirant method reported skin irritation.
Of course, there's a huge array of other products designed to prevent blisters. One study found that a product called Blist-O-Ban reduced their formation, Lipman says — but it's many times more expensive than paper tape.
Lipman says he hopes this research will help more people to reach their finish lines free of debilitating blisters.