I'm new to lap swimming, but I really like it a lot. I have MS, so swimming is the new perfect way to exercise. None of my friends swim, and I've asked probably everyone I know this question. Hopefully you all can help me out. How far is a lap? Across the pool, or across and back? My friends always ask me how many laps I swim, but I always have to answer that I don't know how far a lap is. This morning I swam either 80 or 40 laps. Thanks!