The Hidden Danger of Missing Menstrual Cycles

The perfect end to Yvonne Van Vlerken’s triathlon career would have been in September 2020. After 20 years of winning national titles, completing 17 ironman triathlons in under nine hours and breaking world records, she announced to quit professional triathlon a year earlier, in 2019, to give herself time to recover from something she didn’t know was a problem: a missing menstrual cycle.

“I never got an injury and almost never went to the doctor,” Van Vlerken said. “But I didn’t have a menstrual cycle.”

And the consequences didn’t show until 2017. “There was no night I didn’t have hot flashes because the hormonal issues had gotten so bad. I was 39 and started getting menopause symptoms.”

Amenorrhea, which is the scientific term for a missing menstrual cycle, also seemed to interfere with her wish to get a child. “I wondered if I didn’t get my period, could I get a child? I realized that it couldn’t go on like this”, Van Vlerken said.

After visiting numerous doctors, many of her questions remained unanswered as her problems were put off as a result from her training for long-distance triathlon races. It wasn’t until she did research on her own that she realized her hormonal imbalances were not only due to large training volume. They were also because of her daily habit of doing fasted runs in the morning.

“Many coaches still recommend fasted runs, even though studies show that it is harmful to women,” Van Vlerken said. Referencing Dr. Stacy Sims, author of the book “ROAR”, she said that exercising in a fasted state puts the body under enormous stress. The body produces stress hormones by converting estrogen, testosterone and progesterone into cortisol.

“I started my own coaching program one and a half years ago,” said Van Vlerken. Fifty percent of the female athletes in her team were struggling with their menstrual cycle. “For some athletes, cutting out fasted training is the key to getting their cycle back.” 

But not only fasted training is detrimental to women’s health. “Once your body gets into a relative energy deficiency, the body’s reproduction system is shut down,” she said.

A low energy intake, combined with amenorrhea and a low bone mineral density, make up the female athlete triad–a disorder that often remains unrecognized.

“It makes me sad that many young women don’t get the support from doctors that they would need,” says Van Vlerken.

Too often, they are sent away with a prescription for birth control pills, which will bring back the period. But few doctors realize that they are only treating one aspect of the triad. While it is said that birth control pills help maintain the bone mineral density, studies show that artificial hormones are not as efficient as the natural hormones produced by the body. With a persisting relative energy deficiency and a poor bone health, the female athlete triad can have devastating consequences for female athletes.

Lea Sophie Keim, an elite triathlete for Team Erdinger Alkoholfrei, was sidelined for several months in 2019 when she was dealing with a femoral neck stress fracture. She said the exact causes for her bone injury are complex and shouldn’t be generalized as they range from low bone density to low estrogen levels to chronical undereating. “Nutrition plays a really important role,” Keim said. “I had amenorrhea and was undereating. I didn’t take in enough calories.”

The results of a blood test revealed that her hormones were at a similar level as in women in their menopause. When she got a bone density scan earlier this year, she was diagnosed with osteopenia, the pre-stage to osteoporosis. With most races being cancelled due to the COVID-19 outbreak, she took this as a chance to give her body time to heal. While stress fractures and osteopenia are a common consequence of the female athlete triad, there are side effects that should not be taken lightly.

“I had a chronically low body temperature,” says Yvonne Van Vlerken. “My resting heart rate was around 32 or 34 and I was proud of it because I took it as a sign for physical fitness. But it was actually a sign that my metabolism had slowed down to adapt to the low energy intake.”

It’s a similar story for Lea Keim. “I felt like I was going to freeze when I was swimming in the outdoor pool,” she said. “My heart rate was low and I thought I was in great shape. But my body was just in an energy-saving mode.”

Since her decision to take a break from professional triathlon to focus on her health, she says that swimming in the outdoor pool doesn’t make her feel like “turning into a cube of ice” anymore. An increase in energy intake and decrease in training volume and intensity brought back her menstrual cycle. The third factor in the female athlete triad, a low bone mineral density, will take more time to recover from. “I will take a slow and steady approach to build up my training,” Keim said. “I also check my bone density on a regular basis.”

In the recovery process from osteopenia, she exercises regularly and integrates movement into her every-day life, but she stopped doing high-intensity training. While swimming and cycling make up most of her training, she won’t return to running until her bone health is restored. “I also take two full rest days a week and do yoga,” she said.

Both Yvonne Van Vlerken and Lea Keim agree that more people need to talk about the female athlete triad and its consequences. “I’m still trying to find a way to educate more people on this,” said Keim.

“A missing menstrual cycle is a sign that something is not right,” said Van Vlerken. “And it is dangerous that doctors fail to see the connection of a relative energy deficiency and amenorrhea.”

The miscommunication of possible consequences leads to a large number of untreated cases that might even result in irrevocable conditions such as osteoporosis and premature menopause.

Looking back at 20 years of professional triathlon, Yvonne Van Vlerken said: “I was always very happy about my athletic achievements and I’m really grateful. But the question of how fast I could have been with the right medical support will remain unanswered.”