The bones, muscles, joints, and tendons that make up the foot constitute the most complex mechanical structure in the human body. The metatarsals are designed to spread apart at impact to dissipate shock. When wearing a shoe that is too narrow, our feet no longer have adequate space to spread out. This problem is most prevalent in the toe box of dress shoes, which you can see below. Despite this fact, people still wear shoes, on a daily basis, that are much too narrow for their feet.
Here’s a good rule of thumb: When you flip over your shoe and place your foot flush against the bottom of the outsole, no part of your foot should hang over the perimeter of the outsole. If your foot is hanging over the perimeter of the shoe, then your shoe is probably too narrow for your foot.
A better solution is a barefoot dress shoe.