1) Menstrual cycle
You should have a regularly occurring period every 28-35 days. If your period is irregular, it should be regularly irregular. Less than 3 periods per year signifies amenorrhea.
Estrogen is very important for a runner’s health and performance. The amount of estrogen in your blood changes throughout the menstrual cycle and periods of your life, from pre-puberty to adulthood to menopause, but it should always be in the normal range for the menstrual cycle phase and the specific stage of life you’re in.
Ferritin, a protein in your blood that reflects how much iron your body stores, should be 12-150 ng/ml. If ferritin is low, which is common among female runners, that means your iron stores are low, which can cause iron-deficiency anemia.
Running should give you clarity, control, and confidence in your life, not be a source of negative stress, such as if you don’t perform to your or others’ expectations.