Irritating and troublesome, blisters are not a joy for anyone. If you are a runner, work on your feet all day, or walk a lot, it is never fun to have a blister develop. So why do these painful bumps develop and how can they be prevented? How do you best care for blisters properly before they are extremely painful and debilitating? It's important to always be treating your feet with the best care, so we want to address this painful issue to help with understanding why blisters occur and actions to take to prevent these painful blisters on my feet.
Why do blisters occur?
Blisters are mainly caused by friction, usually your shoes or socks rubbing against your skin. Anything that intensifies rubbing can start a blister, including a faster pace walking, hiking, or running; poor-fitting shoes; poorly fastened footwear (not doing up laces correctly); and the fabric and texture of your sock. Friction can also be intensified by heat and moisture making your feet swell inside those socks and shoes. (1)
It's all really about moisture management and reducing friction.
Actions to take to prevent blisters
As shoes, insoles, and socks work together largely as a unit, it is important to fit the shoe and insole while the sock is being worn. Shoe fit can change depending on what type of sock is worn with the variety of texture, fabric, and fit. (2) The fabric type of socks and the textiles and pattern of the material really make a difference between getting blisters or preventing them.
Socks can serve many functions and the material fibre they are made from is selected for this construction. Socks can be selected for thermal insulation, cushioning, durability, quick drying and ability to maintain shape. These features each demand certain fibre properties. These fibres either can be absorbent (water-attracting) keeping moisture trapped against the skin or non-absorbent repelling water away from the skin.
Fibres that are most absorbent to least absorbent:
Cotton --- Wool --- Acrylic --- Polyester --- Polypropylene --- Nylon
Moisture-Wicking Moisture Gradient (2)
An easy measure you can take to reduce the likelihood of foot blisters forming is to make sure there is no cotton fibre in your socks and instead choose moisture-wicking socks. “Cotton fiber retains three times the moisture of acrylic and fourteen times the moisture of CoolMax®. When exposed to ambient air, socks composed of cotton retain moisture ten times longer than acrylic”. (4,5,6)
"Shoe fit is also super important- as blisters are caused by friction. A Formthotic orthotic placed in a shoe with the proper type of sock could be extremely preventative for blisters as it spreads the load. Spreading the load prevents friction." - Lisa Whiteman, Podiatrist -Resonance Podiatry and Gait Labs, NZ
There have been people who have had success reducing blister formation who have put on double socks, or Vaseline application to their feet, or powders, or antipersperant without a high % of aluminum chloride hexahydrate(this could cause a side effect of skin irritation) . These remedies are not a guaranteed outcome, BUT have worked for some.
Marathon runners and those who live in extremely hot humid areas of the world are at a lot higher chance of forming blisters.
One difficult sport to prevent blisters is marathon running. Ultra runners who are on their feet in the heat can get very moist feet and create more friction with the length of time and distance in running. (7) Wearing Formthotics foot orthotics, adding extra taping to the feet , and definitely wearing socks that wick moisture away from the skin on feet will enable less blisters to form. Extremely humid and hot parts of the world also can create more sweaty feet that can introduce a greater chance of blisters forming with more movement in the shoes if a wicking sock is not used.
"To help prevent blisters, socks need to be hydrophobic (or moisture wicking) – which is the quality of acrylic fibres. Cotton socks are a natural fibre and are hydrophilic which absorbs moisture and holds it close to the skin – and increases the opportunity for blisters. Particularly for marathon runners this is really important as the feet sweat a lot while they are working hard. I know this very well for myself and have scarring where I had continual blisters on my arch and heel. I moved to padded, moisture wicking socks and had much less trouble. I was careful wearing in new Formthotics orthotics so they have time to adjust. When fitted well, the contoured foam surface of Formthotics help minimise friction." - Nicolette LeCren, NZ long distance triathlete
1. Sock fibers should be synthetic with hydrophobic and mechanical fiber qualities for wicking activity.
2. Cushioning within the sock can reduce plantar forefoot pressure forces and associated blisters and skin injuries.
3. Socks, Formthotics, and shoes should be fitted together as a single item.
Comfort is essential to performance, and discomfort increases injury risk because we will adapt our function to minimise the discomfort. So, blister prevention is something that is essential to get sorted if you want to be a happy and healthy athlete.
(4) Naylor P. 1955(A). The skin surface and friction. British Journal of Dermatology. 67: 239–48.
(5) Naylor P. 1955(B). Experimental friction blisters. British Journal of Dermatology. 67: 327–42.
(6) Sulzberger MB, Cortese TA and Sams WM. 1968. Studies on blisters produced by friction II. The blister fluid. The Journal of Investigative Dermatology. Vol 50 No1: 47-53.