Are Callouses Good Or Bad At Preventing Blisters?
Do callouses prevent blisters?
Some athletes swear they keep them blister-free and build their callouses with pride. Others get regular pedicures to keep the hard skin away, especially just before a race.
What is a callous?
Callouses are a thickening of the stratum corneum – the very outer layer of the skin. Thickening of the corneum is one adaptive change research has shown to occur when the skin is subjected to repeated low level frictional forces. I go into further detail in this post.
Callouses image credit
Do callouses protect against blisters?
Callouses protect against abrasions. An abrasion occurs when something wears through the skin - from superficial layers into deeper layers. Like when you fall off your bike and scrape your knee along the road. A callous protects against this because there is more corneum to wear through before getting to raw skin.
But blisters are not a superficial-to-deep wear injury. They're a mechanical fatigue of a skin layer a few layers deeper than the corneum (the stratum spinosum). When there's too much skin stretching of the skin, the structural connections hear tear. Fluid then fills the injured space to form a blister. A callous doesn't prevent this mechanical fatigue. Skin shear happens in exactly the same way whether there's a callous over top or not.
Blister under callous
In fact, the presence of a callous often makes blisters worse. You get callouses where there is a concentration of pressure, as well as other blister-causing forces. So to have a blister under a lot of pressure is never going to be nice! They often turn into blood blisters, too.
The reality is, callouses are far from protective. And a blister under a callus are nasty! They’re very painful and they’re difficult to manage.
How much callous?
We want to benefit from the adaptive thickening that makes the skin more resistant to blisters. But we don’t want to have to build chunky callouses that make blisters more likely. The right amount of skin thickening is barely noticeable.
How do you get rid of callouses?
To reduce the likelihood of blisters, it is advisable that you either see a podiatrist to debride callouses to the right degree. Or maintain them yourself with the use of a pumice stone or emery board.
A final blister tip
Moisturisers won’t make calluses any less blister-causing. That’s because the moisturiser will increase friction levels, which cause blisters. The aim is not to keep a callus soft, but to reduce its thickness.