Is It OK Running Makes Me Miss My Period? No.

By Elizabeth Carey for DyeStat

I'm a runner without a period. Is that healthy?

Short answer: Not likely.

Long answer: Read on. 

Just because something — runners missing periods — is common doesn’t mean it’s helpful. And just because people get awkward or uncomfortable when they hear the word “period” doesn’t mean we can’t talk about it. 

Today we’ll cover what a period actually is (and what it does), define amenorrhea (medical speak for missing periods) and its consequences, and highlight next steps for those of you whose cycle is MIA. 

What is a period, actually, and why should runners care?

Each of us has our own internal biological clock that produces circadian rhythms, including our sleep cycle. The menstrual cycle is another example of how our hormones ebb and flow, sometimes throughout the day or over the course of weeks. Hormones — chemical messengers that circulate in our blood — are produced to regulate and direct the body in many functions. They’re part of our endocrine system, a complex network that works closely with our nervous system (See: fight or flight!). 

Periods are controlled by this system, too — specifically what’s called the hypothalamus-pituitary-ovary axis. Very basically, the brain sends signals (gonadotropin-releasing hormone, GnRH) to the pituitary gland which sends signals (luteinizing hormone, LH, and follicle-stimulating hormone, FSH) to the ovaries, which produce the hormones that prepare the body for potential pregnancy (estrogen and progesterone) with ovulation and more. The levels, ratio, and fluctuations of these hormones feed back into the axis, and the cycle restarts.

Whew, that’s a lot. But stay with me! Because the menstrual cycle and these fluctuating hormones are about more than reproduction. 

They affect your health, growth, and development. They affect your physiology, and therefore training, competition, and even injuries. Estrogen, for example, plays an important role in developing and maintaining your bone density, which you can only boost until you’re about 25 years old. The cycle (and ratio) of hormones also affects cardiovascular health, mood regulation, muscles, metabolism and appetite, thermoregulation, sleep, and immunity. (So, they affect not only how you feel in daily life — see: cramps, bloating, headaches that show up when hormones fall — but also in training and recovery.)  

A period is an important indicator of health, including functioning hormones.   

So what if I lose my period, especially when I’m training hard? 

Amenorrhea is the medical term for missing menstrual cycles. Here are a few relevant diagnoses:

- If you’ve started your period and then miss it for at least 6 months, that’s called secondary amenorrhea. 

- If you’ve yet to get a period by age 16, that’s called primary amenorrhea. 

- If you get fewer than 9 periods per year, that’s called oligomenorrhea, which means it is not regular. 

No matter the specifics, if you’re missing periods or meet any of the criteria above, you should see a doctor or another qualified medical expert. 

While your period may be slightly irregular in its first year or two, your body may settle into rhythms. Track your period and symptoms in a training log or app like FitrWoman to learn what’s “normal” for you. Generally, your first period will arrive one to three years after puberty starts. On average, it’ll last 21 to 35 days, including two to nine days of “bleeding” (one to six tablespoons of menstrual fluid). 

Lacking a period, along with other irregularities, is a key sign that the balance of hormones has been thrown off and the body is under stress. For the record, you should seek medical insight if your periods are:

• Not happening
• Frequently unpredictable
• Shorter than 21 days 
• Longer than 45 days
• Come with severe symptoms like pain, anxiety, or dizziness 

Ideally, see a medical pro who works with female athletes, especially those in your phase of development (like adolescence). Look for board- and state-licensed and otherwise credentialed folks like MDs, DOs, and NPs; specialists include endocrinologists and sports medicine doctors. She should be familiar with Relative Energy Deficiency in Sport (RED-S) or, at the least, aware of the Female Athlete Triad.

She should help you identify or rule out medical issues that can caused skipped periods, such as:

• Pregnancy
• Stress
• Illness
• Medication, including hormonal birth control
• Polycystic ovary syndrome (PCOS)
• Endometriosis
• Thyroid and other endocrine conditions

Amenorrhea is also a red flag for RED-S, a syndrome that compromises health and performance. It’s caused by low energy availability (LEA) — aka not consuming enough fuel for your body to go about all of its business. When your body is stressed, specifically if it is under fueled and/or training hard, it does its best to survive and conserves whatever energy it can to preserve key functions (like your heart beating and your brain thinking). That’s why it may shut off several functions and stop sending hormone messengers, including those that trigger your period. 

Remember: You need to eat and hydrate your body to live (think: your organs), to grow (see: adolescence), to run (and lift and race and foam roll), and to do all your other activities (study, tweet, whatever). Work with a registered dietician (specifically one who specializes in sport and eating disorders, ideally with an Intuitive Eating or Health At Every Size approach) if you have questions about your individual needs. 

Seek Advice

Missing periods is not a blessing for runners. Rather, it’s a sign that you should see a doc to rule out medical issues and, perhaps, fuel more to avoid health and performance declines. 

What questions do you have about periods and running? Comment below or holler at us on social:

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Elizabeth Carey is a freelance writer and running coach based in Seattle, Washington.