Excessive exercise can contribute to missed menstrual periods, even for women who are on birth-control pill. A too-high or too-low body-fat percentage can also cause missed periods. If you are on a birth-control pill that allows time for a period and you are not getting one, visit your gynecologist to determine the cause.
Amenorrhea
Amenorrhea is the absence of periods and is a warning sign that your body is doing too much. During times of physiological stress, your body will shut down bodily functions that aren't necessary for survival. Menstruation is meant for reproduction and is not required for your body to live. Therefore, your periods are one of the first things to go when your body is under stress.
Period Requirements
A certain amount of calories, protein and body fat are necessary to maintain menstruation. Healthy women who aren't necessarily athletes should have a body-fat percentage between 21 and 31 percent; a woman's essential body fat is between 10 and 12 percent, according to the BMI Calculator website. If your body fat is in the essential range or lower, you might be at risk for amenorrhea. When your body fat is too low, your body quits making estrogen, which is necessary for ovulation and menstruation. Excessive exercise coupled with too few calories throughout the day will inevitably lower your body-fat percentage.
Excessive Exercise
What is considered excessive exercise for one person might not be for another — an endurance athlete, for example, will be used to lengthy daily workouts, where the average woman might be used to a basic 30 minutes four or five times a week. Your body uses its natural glycogen stores, which typically come from carbohydrates, as a source of fuel during your workout. Dr. Jeff Benson explains that after 90 minutes, your glycogen stores are typically used up and your body will start burning muscle for energy instead. Exercising longer than 90 minutes daily can thus be considered excessive and even detrimental to your muscle mass and bone density.
Advantages to Exercise
Exercising during your period can actually relieve cramps, bloating and headaches associated with your cycle. The endorphins released during exercise can also improve your mood. Exercise will generally not affect someone's cycle, whether she is on birth control or not. But if you start to miss your periods and you are on birth control, it is time to visit a doctor and consider how exercise might be factoring into these effects.
