Jogging?

I have a regular brisk walking routine, but lately, I have felt like breaking out into a jog. I have lost a lot of weight, but I am still 100 lbs overweight, so I was wondering if it would be safe to do, or should I wait until I lose some more weight? How will I know when it is ok to do?

Try it and find out! Take it easy and see how it feels. You're almost certainly not going to injure yourself by jogging a block or two.

If you want to take up running, look up the Couch to 5K program. I finished it a couple of years ago at ~100 pounds overweight.

Your body will tell you pretty quickly if it's something you should not be doing (knee pain, e.g.) - I'd give it a try! Start with intervals - alternate walking with short intervals of jogging.