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The health risks of overexercising and undereating

Overexercising and undereating, which can cause relative energy deficiency in sport (RED-S), can affect fertility, bone density, energy levels and all body systems.

Auckland personal trainer Nats Levi wasn’t worried when her periods got lighter and her menstrual cycle became less regular. In fact, she was quite pleased. She saw it as proof that her intensive exercise programme was working.

“There’s this untalked-about assumption that you will lose your cycle or it will be quite light if you’re exercising a lot. It’s kind of seen as being normal,” she says.

It wasn’t until she went to see an endocrinologist for fertility advice that she learnt that her disrupted menstrual cycle was the symptom of a condition that was compromising both her ability to conceive and her bone health, increasing her risk of stress fractures and osteoporosis.

Nat Levi. Photo/Supplied

Previously known as female athlete triad (FAT) – because it was thought to have three components: menstrual dysfunction, low energy availability and loss of bone density – the condition is now often called relative energy deficiency in sport (RED-S). That’s partly because it can also affect men (minus the menstrual dysfunction), but also because it has more than three components.

“It’s now recognised that it affects all the main systems of the body,” says University of Waikato sports researcher Holly Thorpe. “It can affect the cardiovascular system, the immune system, the endocrine system, gut health, growth and development and how you respond to injuries.”

But whatever the condition is called, there’s no doubt about what causes it: undereating and overexercising.

“I was eating but I was not nourishing my body properly because of the sheer volume of exercise I was doing,” says Levi, who has written a book, From F.A.T. To Fierce, about how to overcome the condition.

Holly Thorpe. Photo/Supplied

To get better, she had to reverse her previous behaviour and start eating more and exercising less. She cut her exercise programme from about 15 fitness classes a week to just one, along with three weight-training sessions and taking her dog for walks. She also changed her diet, including upping her carbohydrate intake.

Paradoxically, her new regime saw her losing weight, rather than gaining it. According to Thorpe’s University of Waikato colleague, sports physiologist Stacy Sims, it takes just four days of low-energy intake for the thyroid to stop working. This can cause tiredness and underperformance, and it can also lead to weight gain, particularly belly fat or fat at the back of the arms.

“You think the belly fat must be because you’re not training enough, so you stop eating as much and you train harder, which just perpetuates the low-energy state.”

Recent University of Otago research suggests up to 45% of exercising women may be at risk of RED-S, either by accident – they simply don’t realise they are not eating enough to support their level of activity – or on purpose. In some sports, such as long-distance running, swimming, gymnastics and ballet, where low body weight is seen as integral to success, 70-100% of participants are at risk of RED-S. Many also have eating disorders.
Stacy Sims. Photo/Supplied

Thorpe says accidental RED-S is relatively easy to treat by adding extra calories to the diet, preferably with help from a nutritionist. However, treatment is more complicated if someone is deliberately not eating enough. For young women athletes with ambitious goals, being told to eat more and exercise less – or even to stop competing for a while – can be devastating.

“It’s a very tense decision and often sports doctors have to make it. There’s often a lot of crying and emotion.”

However, before that can happen, an athlete needs to recognise that they are suffering from RED-S in the first place. In women, the first sign is menstrual disruption, though this important early-warning sign is masked if they are taking an oral contraceptive pill. Thorpe says exercising women should track their periods to alert them to any irregularities. The second warning sign – for men as well as women – is when they start to get stress fractures.

The good news is that it is possible to reverse both the hormone and bone effects caused by RED-S. But for elite athletes, that may require a fundamental change in attitude.

“Coaches and athletes are very focused on the short term. They can justify damage because they are pursuing excellence, so it’s harder to think critically about what will happen in the long term,” says Thorpe.

This article was first published in the November 16, 2019 issue of the New Zealand Listener.