Running and the Menstrual Cycle

Just as the effects of menstruation itself differ greatly from woman to woman, the effects of menstruation on running performance vary greatly as well. some women notice no difference in performance; others notice a great deal of difference. If your period is going to affect your running, it’s most likely to occur during the premenstrual and early flow phases of the cycle. The good news is that many women runners find that their running helps to ease cramps, bloating, headaches, fatigue, and all of those other friendly monthly visitors. To best deal with the effects of menstruation, track how your cycle affects your running in a training log, and then plan accordingly. For example, if you notice that running often seems harder during your premenstrual phase, accept that and don’t try runs that are longer or harder than usual during this time.
On the not-so-good side, running can lead to increased bleeding. Some of the painkillers, such as ibuprofen, that help with other side effects can also reduce bleeding. The increased bleeding usually isn’t so great that it’s visible. But if you’re worried about this, do what Olympic gold medalist in the marathon, Joan Benoit Samuelson, does and run with a tampon in a plastic bag pinned inside of your shorts or tights. Women runners sometimes don’t have periods. This condition is called amenorrhea, and although it might sound like a dream come true, it’s not good. It usually means that little or no estrogen is circulating in your body, which can lead to your bones becoming weaker, as well as short-term infertility.
The causes are complex, but most experts think that amenorrhea is caused more often by not eating enough than by exercising too much. Running alone can’t be named as the cause, given that some women train more than 100 miles a week and still have regular periods. If your periods stop or become irregular (more often than every 25 days or less frequent than every 35 days), see a doctor. Just don’t let him or her convince you that running is solely to blame.