As best-selling author John Gray so decisively pointed out, men and women are from different planets. So why do all coaches and running books take a one-size-fits-all approach to training? As a woman, here are six general things you need to know about running and the female body.
Estrogen is the single biggest thing that differentiates you from that guy running next to you in a race. It is a powerful hormone, influencing many aspects of a woman's physiology, from metabolism to glycogen storage to lung function to bone health. A runner-friendly hormone, times of the month when estrogen is high (just before ovulation at the end of the follicular phase of your menstrual cycle and the middle of the luteal phase) are good times to focus on hard workouts and races.
Menstrual Irregularities for Runners
Many female runners who train hard and frequently and have a low body fat percentage often experience irregular or even absent menstrual cycles, which reduces estrogen levels. Any disruption to your menstrual cycle can decrease your bone mineral density, increasing the risk for osteoporosis and stress fractures. Estrogen is extremely important in facilitating the absorption of calcium into bones. Female distance runners with irregular or absent menstruation have significantly lower bone density than those with regular menstruation, and even compared to non-athletes.
If you're at risk for a stress fracture because of a loss of estrogen, you need to do everything you can to strengthen your bones and prevent a stress fracture, including adequate intake of calcium and vitamin D, and strength training. You may also want to take oral contraceptives, which supply you with estrogen.
If you bleed a lot during menstruation, your blood's hemoglobin concentration may decrease, which can negatively impact your ability to transport oxygen in your blood. Since iron is an important component of hemoglobin, iron loss often accompanies a lot of bleeding. If this happens, you may need to supplement your normal diet with iron. Many female runners exhibit athletic anemia (low blood iron levels due to physical activity), especially if they lose a lot of blood during menstruation. Athletic anemia is very common among female runners, especially those training at altitude.