What's important is that you try to find some way to exercise daily and that your shoes fit well and properly protect your feet. Some athletic shoes are designed for specific activities, such as running, walking or biking. The sole is the bottom of your shoe where the rubber meets the road, so you want it to cushion your foot well. It should be padded and removable. It's the most important part of the shoe.
Many manufacturers develop special cushioning devices as part of the midsole.
Make sure your shoe has a good heel counter, too. That's the firm cup surrounding the heel to keep it stable. If you have special foot problems and can't get comfortable shoes, consider seeing a podiatrist or sports podiatrist who can fit you with orthotics, special inserts that fit inside your shoe. Form and Function Look for these features in specialized athletic shoes.