Will I need extra iron when I start working out?

Yes, if you’re not getting enough. Women who are capable of becoming pregnant are prone to iron-deficiency due to not getting enough through food and because of monthly losses due to menstrual cycles. Women ages 19 to 50 years need 18 mg per day and those over 50 years need 8 mg/day. If you're pregnant, you need 27 mg/day and your doctor may prescribe a separate iron supplement. If you're breastfeeding, you don't need as much (9 mg/d) because menstrual cycles stop while breastfeeding.

For women of childbearing age, blood loss through menstruation can lead to iron deficiency, one of the types of anemia. The Institute for Medicine of the National Academies recommends a daily allowance of 18 milligrams (mg) of iron for women aged 19 to 50. However, moderate fitness programs do not specifically increase your iron needs. With more rigorous training, iron loss can increase with sweating. If you are working out really hard, make sure you include lots of iron rich foods like red meats, most legumes (kidney, lima, pinto, navy, black and soybeans), dark greens (collard greens, kale, mustard greens, spinach, and turnip greens) tofu and certain vegetables (broccoli, Swiss chard, asparagus, parsley, watercress, Brussels sprouts) as part of your regular diet.