It is important to wear the proper fitness shoes/sneakers for the respective fitness activity. Wearing the proper fitness shoe will help you maintain good posture while reducing stress on your lower back and knees. Think about it… would you play golf with a tennis racquet? You could do so, but it would not be very efficient or even safe. The same logic applies to footwear.
A runner should wear running sneakers (instead of walking sneakers) because they provide heel cushioning and support where the foot first impacts the surface. If you are an avid walker, you should wear walking sneakers that allows the foot to flex during a workout. Walking sneakers provide cushioning in different areas of your foot, as your running gait is different than that of walking. If high impact cardio workouts are your sport of choice (such as a step or kick boxing class), look for a shoe/sneaker that provides extra cushioning in both the heel and forefoot.
After choosing the right shoe/sneaker for a given fitness activity, make sure the shoe fits properly. Bring your old pair of shoes with you. A good salesperson can evaluate your old shoe style and size and recommend a new shoe that will fit your properly.
A shoe is too big if your heel slips out of the shoe while walking and if you are able to insert one finger between your heel and the back of the shoe. Likewise, if your toes hit the front of your fitness shoe while standing, the shoe is probably too small. There should be one finger width between the front of the shoe and your toes. Do not buy shoes that feel tight and think they will stretch… you should feel comfortable in the shoes the day you purchase them.
It should be noted that most people have one foot that is larger than the other, so make sure to try both the left and right shoes on prior to buying then. Do not worry if your foot size increases… age and life changing events such as being pregnant can increase the length and or width of your foot.
So get out there and take a brisk walk at sunset, try a new step class at the gym or run your opponent all over the tennis court with your new, sport appropriate fitness shoes!