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Studies may link athletes and hypothyroidism

Posted June 11, 2007 at 10:00 AM by Katie Drummond

Section: Her Fitness, Her Health, Her News, Special Features

My mood was great, my weight was fine, and my running times had never been better – I was in the best shape of my life. So why was I in my doctor’s office, being told I had hypothyroidism? How does a 21-year-old, daily runner with energy to spare wind up on medication to treat a condition commonly associated with middle age, lethargy and weight gain?

It might sound surprising, but my situation is far from unique. As more and more athletes are being diagnosed with hypothyroidism, medical professionals are starting to make the connection between intense training (around 50 miles of running a week) and a malfunctioning thyroid gland. Recently, elite athletes Galen Rupp and Adam Goucher were both diagnosed with the condition – surprising, considering they are two of the best competitive runners in the country, and they hardly fit the typical profile of people diagnosed with hypothyroidism.

But this image is starting to change, as many doctors are now calling hypothyroidism the “unsuspected illness” that may affect many more than the 5 million Americans currently diagnosed with a slow thyroid. Although the exact cause of its occurrence in competitive athletes hasn’t been determined, speculation suggests that the ongoing stress of training might interfere with the regulation of this important hormone – much like some female athletes develop amenorrhea when intensive activity suppresses estrogen levels. Because the thyroid is mainly responsible for metabolism, which is stimulated by exercise, enough physical strain might mean the thyroid loses its ability to slow down and speed up properly – which, for some athletes, means the development of a sluggish gland.

Further research shows that poor diet may also play a role – a 2005 study on the connection between intense exercise regimens and the thyroid gland also found that athletes whose caloric consumption wasn’t enough to fuel their workouts were prone to hypothyroidism. In fact, female study participants who ate insufficient calories for merely four days during which they engaged in their usual intensive training routine developed abnormal and suppressed thyroid levels.

The production and release of the thyroid hormone (called thyroxine) is complicated, and hypothyroidism can develop in several ways. For some, the pituitary gland or the hypothalamus doesn’t produce enough stimulating hormone (TSH) to get the thyroid gland pumping thyroxine through your body. The illness also occurs if the gland itself malfunctions – which seems to be the case in athletes. In this situation, a blood test of TSH levels will show them to be elevated, meaning the body is producing more TSH to speed up the thyroid. But because hypothyroidism can develop at so many stages of thyroxine production and release, other tests might be necessary to reveal a problem.

The list of symptoms associated with hypothyroidism is lengthy, and there’s no way of telling which ones a patient might develop, although more indicators usually crop up the longer it goes untreated. Early symptoms usually include weakness, depression, brittle hair and nails, and unexpected weight gain – unfortunately, these signs are vague and can be caused by a number of other health problems, making hypothyroidism particularly difficult to detect until more serious symptoms, like slowed speech and facial bloating, make an appearance.

Both Rupp and Goucher have cited low energy levels and sluggish training sessions as the first signs of trouble with their thyroid levels. For me, it took two years and several blood tests before my doctor suspected that the thyroid was to blame for my thinning, brittle hair – the only symptom I seemed to have, and one which can be caused by a number of other, more minor problems, like stress or changes in diet. While I didn’t have any of the risk factors for hypothyroidism, if you have a family history of the ailment or are over 50, your chances of falling ill more than double.

Fortunately, treatment for hypothyroidism is as simple as a daily dosage of thyroxine. That being said, it can take months for doctors to determine how much is enough – or too much. Too high a dosage can trigger hyperthyroidism, characterized by heavy sweating, shaking, weight loss and insomnia, and too low a dosage means you won’t be relieved of your original symptoms. Once you find the right dose, you’ll need a blood test every six months or so, as your body’s ideal thyroxine levels might change as you age or alter your lifestyle, eating, or exercise habits.

If, like me, your hypothyroidism can probably be blamed on your activity level, you don’t need to slow down – but you do need to recognize that treating athlete-induced hypothyroidism comes with complications. Some medical professionals suspect that exercising after taking thyroxine limits absorption, as digestion slows down during intense activity. Furthermore, many athletes eat a healthy, high-fiber diet – which can also reduce absorption. The solution for most is simply to take a higher dose of medication, but this might mean allowing more time for doctors to find the right dosage to suit your lifestyle.

Chances are, your sluggish workout can more likely be blamed on that late night out or that second piece of chocolate cake, but if you do notice ongoing changes in your performance, it can’t hurt to have your thyroid checked. Competitive athletes may not fit the description of one suffering from hypothyroidism, but if ongoing research into the link between intense training and a malfunctioning thyroid proves right, that description might soon need to change.

Further Information:
Study on the link between athletic training and thyroid levels:
Exercise intensity and its effects on thyroid hormones
Information on the thyroid and hypothyroidism:
www.allthyroid.org
www.endocrineweb.com
Adam Goucher and Galen Rupp:
Mensracing.com interview with Adam Goucher
USATF bio of Galen Rupp

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Tags: adam goucher, galen rupp, hypothalamus, hypothyroid, hypothyroidism and athletes, hypothyroidism symptoms, pituitary gland, thyroid, thyroxine, tsh

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