Shoes that are too small, in length or width, may cause blisters under the toes and on the ends of the toenails. When fitting shoes, select a size with a thumbs width of space between the toes and end of the toe box, this is to allow your feet to expand. During a day on your feet and during exercise, your feet will expand by between a few millimetres and in some people up to 2cm. The forward motion of running tends to move your toes forward in your shoes, and the recommended thumbs width space allows for this movement, especially important when running downhill.
Old and worn out shoes can cause blisters, as they become stiffer and less forgiving to your feet. Change shoes every 500 miles or 2 years, whichever is sooner.
New shoes & Races
Moisture and friction encourage blisters, hence many runners only suffer blisters during races, especially marathons. You’re perspiring more, running faster and longer, sloshing through water stations and, if it’s warm, pouring water over your head. Try to avoid running through water during races, and don’t wear new running shoes for a race; always ensure that you run at least 50 miles in them before you run a race or a long run.
Tying Your Laces
Wearing your laces too loosely can result in a loss of stability and over pronation (foot imbalance), and the movement this allows can cause blisters.
Running socks will help prevent blisters, by keeping your feet drier and prevent your feet slipping in your shoes. Synthetic running socks wick moisture away from the skin, cotton may be lighter but it retains moisture, and silky cotton socks will allow your shoes to slip creating friction and blisters.
Socks with reinforced heels and toes also help reduce friction.
Your socks should fit smoothly, with no extra fabric at the toes or heels.
The Wrong Shoes
When buying shoes go to a specialist running store for advice on picking the right shoe for you and how you run. Wearing neutral cushioning shoes can cause blisters under the arch if you need supportive shoes, as the neutral shoe won’t be preventing you rolling in on foot impact. Supportive shoes, are supportive to different degrees, and therefore it is important to find out how much support you need and which shoe suits you.