I think you also want to ask what is best for you personally. I was a walker and then worked my way up to jogging. However I found that because I didn't like jogging that I lost my consistency in my workouts. So back to walking. I also found I can keep walking and increase my HR and calorie burn by using the incline on the treadmill. You will have to walk longer than you would have to jog for to get the same calorie burn but again if walking is your thing, you won't mind.