Skin Toughening To Stop Blisters: How Can I Do It?
Tough skin is more resistant to blisters, for sure. But it might not occur in the way you might think. In this article, we’ll talk about what it takes for skin toughening to occur, including the breaking in your shoes, pre-conditioning, adaption and callouses. Finally, we’ll cover what most people expect skin toughening to stop blisters to be all about – skin drying techniques.
Skin toughening research: Pre-conditioning and breaking in shoes
Here’s what the research shows about time spent in your shoes, training and blister incidence:
- Van Tiggelen et al (2009) found previous hiking or military experience offered some protection to blister formation
- Brennan et al (2012) determined that troops who did not “break in” their boots were more likely to suffer with blisters
- Paterson et al (1994) found that military cadets who wore their boots less than 20 hours per week in the 2 weeks leading up to training were more likely to get foot blisters
- In testing double sock systems against standard military issue socks, Thompson et al (1993) found reduced blister incidence was most noticeable early on in recruit training, when “recruits are adapting to the rigours of physical training and acquiring their military skills.”
- Gardner and Hill (2002) found hikers who had not preconditioned their footwear were more likely to get blisters (32% versus 25%)
Your skin adapts to blister-causing forces
Skin adapts to the forces placed upon it. It has been found (MacKenzie, 1974; Jagoda et al, 1981; Sanders et al, 1995; Knapik et al, 1996) that when the skin is subjected to repeated low level frictional forces, the following changes occur:
- Epidermal cell turnover is faster
- Cells are more resistant to frictional forces
- And the epidermis becomes thicker
What’s more, these adaptive changes in the epidermis take place sooner than you might think. MacKenzie (1974) examined changes to the skin of mouse ears that were rubbed every day 10 times with a moderate force (so as not to cause skin damage). Skin characteristics were observed at day 1, 7, 14, 28 and 35. What MacKenzie found, in fact, was there were more cells in the epidermis. And they were larger and more resistant to mechanical damage, compared to ears that received no rubbing. The interesting thing to note was, the changes at 7 days were identical to those at 14, 28 and 35 days. And this was with just 10 rubs of moderate force per day!
The first few days
Reported in the graph below are the number of blisters that occurred during a road march. The number of blisters were recorded at the end of each day. This was a 21 day, 580km road march in Korea undertaken by college students (Choi et al, 2013).
Of the 142 college student participants, 135 suffered with blisters. That’s a massive 95.1%. What’s more, ninety percent of blisters occurred in the first five days, with day two having the highest incidence. After that, there was a significant tailing off. So day 2 it the peak of new blister incidence.
While there were less than ideal aspects to this event*, an adaptive response has to be at play here.
*Shoes were provided to all participants and for some reason, cotton socks were worn in spite of an average humidity of 93% – what were they thinking?
Similar results were found by Reynolds et al (1999). They studied injuries in a group of 218 male light infantry soldiers on a 5-day 161km cross country march. Forty three of 45 blisters occurred on day two of the march.
“Skin toughening” or “skin drying”
“Skin toughening” is a phrase commonly used to describe the effect of astringent preparations. For example, alcohol foot soaks, salt water or black tea foot baths, Friars Balsam, Akileine Tano and others (Read, 1990; Vonhof, 2012).
However, an exact blister prevention “skin toughening” mechanism of action is not clear. In fact, it hasn’t even attracted any expert commentary, that I can find. And there’s no blister or skin friction research that has tested these astringent preparations (Knapik et al, 1995).
One thing I can tell you is these astringents have a “skin drying” effect. Dry, rather than moist skin certainly means lower friction levels. And we know that means less blisters. But does it mean tough skin? Read this article for more on skin drying strategies.
Spending time in your shoes for as little as a week will kick-start a natural protective adaptation of the skin to blister-causing forces. You can extend this to socks, insoles, running distance and whatever activity you’re involved in. Make changes small and slow – to benefit from the gradually increasing resilience of your skin to blisters.
Depending on your individual blister threshold, this protective mechanism may not provide full blister protection. The research results quoted earlier show a somewhat reduced blister incidence, but not a zero blister incidence. Look again at the results of Gardner and Hill (2002). Even after “breaking in” footwear, there was still a 25% blister incidence (compared to 32% without breaking them in).
The take home message here is, the adaption of your skin that comes with “breaking in” shoes and with other aspects of training is a step in the right direction and should not be neglected!
So whether it’s new shoes, different activities, longer distances or more challenging terrains – they all exert new shear loads to the skin. Getting your skin “used to” these new forces by making gradual and incremental changes can help protect your skin and make it more able to resist blister formation … up to a point!