Runners sometimes hear that it is important to buy running shoes with little extra space for the feet. The thought is that feet swell during running, which can irritate the skin and cause blisters. But is it true that feet swell during running? The answer is: it depends.
In a recent study, the precise foot volume of twenty-eight runners was measured prior to a 10k run. The foot volumes of the runners were again measured immediately after the run, and no difference was discovered.
The study did mention that other studies have found changes in foot volume after runs shorter than 10k and a decrease in foot volume after marathons. The decrease in volume for the longer distances is generally attributed to dehydration – the loss of water through sweat decreases volume size of the feet. The authors theorized that the 10k distance may be an “equilibrium point” between foot swelling at the beginning of a run and a decrease in volume size after a long distance.
The study also found that a runner’s foot volume also depended on the outside temperature. Hotter temperatures lead to greater dehydration and a decrease in volume.
What’s the take away? Well, there is some evidence to suggest that foot volume does increase during the initial stages of a run, but that volume actually decreases for distances more than 10k – especially when running in hot weather. Therefore, according to research, there really is no reason to go out of your way to buy running shoes that have extra foot space. Rather, choose shoes that feel the best on your feet.
