Excessive perspiration of the foot can lead to a build up of moisture in the shoes. This in turn, leads to an influx of bacteria causing shoe odor issues.
Shoes are designed to keep moisture out. It's their insulating properties which also keeps moisture in, exaggerating the issue. Some materials in the shoes absorb moisture thereby providing bacteria with an ideal place to grow. Products such as Shoe Spray, Shoe Powder and Odour Guard Insole can help solve bad smelling shoes and footwear.