Exercise and Skipped Periods

Question

I’ve been on the track and field team at my high school for several years but only recently started running the 10 kilometre races. Although I got my period when I was 14 and my cycles have been somewhat irregular, I’ve not totally skipped periods until recently. My mother got worried and took me to the doctor. She checked me carefully, did a blood test for the pituitary hormones prolactin and thyroid stimulating hormone (TSH) that were normal, and said I seemed healthy. However, she also said that I should stop training until my periods became normal again. I don’t want to stop running. Do you think I have to?

Answer

Thanks for your question. It’s a good one.

I can’t answer it without knowing a few more things about you and your life. The first thing I need to know is your body mass index (BMI) that is based on your weight and height. Ideally you would have a BMI of 19-22 at your age. BMI is calculated by taking your weight in kilograms and dividing by your height in metres squared. If your BMI is lower than 19 or you’ve recently lost weight then I would first work hard to gain to a normal weight. A healthy way to do that besides regular meals is to have snacks of things like almonds or peanuts or sunflower seeds between meals.

Another thing I need to know is what you’re doing. Likely you are in your final year of high school with Provincial exams looming. You may also be wondering about what to do next year or applying for jobs or further schooling. That can be very stressful and all by itself may make your periods stop. It would not be uncommon for you to be having conflicts with your parents or to have just broken up with a partner. These emotional stresses are as hard or harder than running on your menstrual cycle.

I wonder if you are worried about your weight? Worry that what you eat may make you fat is called “cognitive dietary restraint” and is common in women of all ages. Restraint is often present in women whose weight is normal. Eating restraint appears to cause ovulation or menstrual cycle disturbances (1). These reproductive changes are linked to bone loss (2). Even before the first period, eating restraint is hard on bones (3). Although women with eating restraint tend to exercise more (2), but restraint, not exercise is causally related to changes in ovulation and bone loss.

So—back to whether or not you should stop running. I don’t think you should, especially given that it seems to provide you with a feeling of accomplishment. However, I suggest that you do longer runs only once a week until your period comes back. Do sprint training on another couple of days a week and weight training on the rest. That will allow you to gain some weight if you are underweight, and it will allow your period to re-start. I’m very sure that your period will come back, your bones will become strong if you follow the ABCs of Osteoporosis Prevention in Young Women and one day, if you want, you will be able to have children.

Hope this is helpful for you.

Reference List

1. Barr SI, Janelle KC, Prior JC. Vegetarian versus nonvegetarian diets, dietary restraint, and subclinical ovulatory disturbances: prospective six month study. Am J Clin Nutr 1994; 60:887-894.
2. McLean JA, Barr SI, Prior JC. Dietary restraint, exercise and bone density in young women: are they relate? Med Sci Sports Exerc 2001; 33:1292-1296.
3. Barr SI, Petit MA, Vigna YM, Prior JC. Eating attitudes and habitual calcium intake in peripubertal girls are associated with initial bone mineral content and its change over 2 years. J Bone Min Res 2001; 16:940-947.