I ran almost every day for years. I am working on rebuilding my running habit now. I would say that for people with a lot of running experience who are in good

I ran almost every day for years. I am working on rebuilding my running habit now. I would say that for people with a lot of running experience who are in good shape, one mile every day is going to do no harm at all. edit to add: I feel I need to put a disclaimer here. People new to running, especially overweight people, should not run every day. Knee and ankle injuries are very common.