Low iron can affect your blood supply and how much oxygen binds to your RBCs. Low oxygen can cause all sorts of issues like fatigue and higher heart rates/blood pressures. Right now since you're borderline, you probably won't feel anything, but eventually the body can't compensate effectively. It's always best to keep our blood products where they need to be! I'd recommend eating high iron foods or supplements after talking with your doctor. Gotta take care of yourself before you can take care of others cars! Also preventative costs are always much cheaper than corrective costs, if that helps persuade you.