After my knee surgery (meniscus cartilage tear/repair) and after my appendectomy, I was pretty keen to get up and moving so that I could go outside and smoke. Both times the nurse commented that while smoking on its own isn't great for healing, the fact that it forces you to get up and moving quickly and frequently is generally helpful. In both cases the doctor was quite surprised at how quickly I'd healed up when I went for the follow-up/stitch removal.