While we've all heard that running shoes break down after logging lots of miles (about 300 to 350), you may still be holding on to your fave pair. (They fit just right! They're so cushy!) Not a good idea. Glue has a tendency to break down under ultraviolet light, as do the other materials that make up the shoe.
Running shoes are like the tires on your car, old tires have worn tread and can be dangerous to drive on, especially if you are driving in weather condiitons that are something other than a bright sunny day. Running shoes, while they may not be as dangerous in bad weather, break down like tires do and need to be replaced in order to prevent injury.The general rule is to replace your running shoes every 300 to 400 miles. The reason for this is in that time, shoes tend to losee their cushion and stability which can lead to knee pain, shin splints, and foot pain.
Sit at a desk all day? Wear high-heel shoes? This can be bad for the body. You may not realize it but even sitting requires your muscles to work to keep you in that position. Sitting at a desk all day can lead to muscle imbalances that affect your posture, the way you move and will lead to muscle aches and pains and even make you more susceptible to injury.
When I was young, I wore high heels – a lot. Fortunately, because of many recreational interests, I also wore regular shoes or tennis shoes (that’s what we called it then) very often and have not suffered the foot deformities that I see quite often and which are usually the result of fashion footwear. At this point, let’s not go into all the resulting misalignments of the rest of the body.