I don't know how you run, but it's important to do it correctly or you could have knee/ankle issues.

I personally think if you are not training for a race, you should jog for exercise instead of running. When you jog, it should be coming down on your feet from heel to toe, in a smooth, rounding way. Avoid bouncing up and down; that increases your chance of knee injury.

Make sure you're wearing athletic shoes specially designed for jogging. Jog in them for a few yards in the store to make sure they are comfortable and feel right with the way you would jog.

I hope this helps you out. I've been a jogger for about 15 years now (off and on, according to my busy schedule), and I love it. I've never had an injury.