Iron and thyroid function

Iron deficiency is one of the most common issues athletes face.  Iron and thyroid health go hand in hand and the effects of exercise on the thyroid gland and hormones are not well understood.

Iron and thyroid function 
Undiagnosed iron deficiency presents an increased risk of impaired thyroid function. Active women have high-energy lives, managing work, family and training, and many will accept low energy and brain fog as simply a result of being overworked or as an inevitable part of hormonal changes.

However, low thyroid function, iron deficiency, overtraining and hormonal changes also present with many of the same symptoms.

Signs that your thyroid function may be underactive (hypothyroid) include fatigue, unexplained weight gain, headaches, low blood pressure, dry skin, constipation and cold intolerance. These early signs of cellular hypothyroidism can appear when blood pathology remains within standard ranges.

As with most chronic issues, there are multiple factors that may contribute to dysfunction.

The Link between Exercise and Thyroid Function

In athletes, endurance and high-volume training promotes thyroid function. During exercise, your hypothalamus stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH), which in turn signals your thyroid to synthesise and release the thyroid storage hormone T4 and active thyroid hormone T3.

These hormones influence your body’s metabolism and allow it to increase exercise intensity. Over time, this repeated, high demand of your thyroid during prolonged intense exercise may impact your thyroid function, causing it to slow down and consequently lose the ability to produce sufficient hormones.

Iron and Thyroid Function

Normal thyroid function is dependent on several nutrients to regulate the synthesis of thyroid hormones. Iodine, iron, tyrosine, selenium, and zinc are needed to facilitate the conversion of T4 to T3 . A deficiency of any one of these nutrients would result in reduced T3 production, causing you to experience hypothyroid symptoms. Vitamins A and D also play important roles in cell receptor behaviour to regulate thyroid hormone metabolism.

While iodine is the key mineral for healthy thyroid function (read more…here)  it is not uncommon to find iron deficiency in hypothyroidism. Although widely recognised for its influence on red blood cell production, iron is also an important component of thyroid peroxidase, an enzyme essential for thyroid hormone biosynthesis.

Iron deficiency interferes with the normal functioning of the thyroid, contributing significantly to fatigue, exercise intolerance and lightheadedness.

Increased menstrual bleeding can lead to iron deficiency. Many of us dismiss low energy as a symptom of a busy, active lifestyle and so iron deficiency frequently goes undiagnosed in perimenopausal women.  For athletes, iron plays a critical role in exercise performance as outlined in our blog “Increase your iron absorption and rebound from anaemiahere

The most common causes of iron deficiency include inadequate dietary iron intake, inflammation, poor iron absorption in the gut, parasites, iron loss through sweat, urination and faeces, blood loss through menstruation. Pregnancy, breastfeeding or high-volume exercise will also significantly increase iron demands. Take our free anaemia quiz to see if you may be iron deficient here

Thyroid Function and Sex Hormones in Women

Your thyroid function is sensitive to fluctuations in sex hormone levels, particularly oestrogen. Oestrogen stimulates the production of the thyroid hormone precursor, thyroglobulin, and increases the protein that carries thyroid hormones in your blood.

As oestrogen changes (such as during peri-menopause) so too does thyroid hormones, which play an important role in metabolism, muscle strength, energy production and expenditure, heart function, and temperature regulation.

As oestrogen levels rise and fall later in life, menstruation may become irregular and heavier. Peri-menopausal women may experience symptoms for over ten years as described in our blog on “Natural solutions for menopausehere .

During peri-menopause declining oestrogen may impact thyroid function and can lead to inadequate production and circulation of thyroid hormones.

Exercise During Hormonal Changes

Despite common misconceptions, women can train and perform well throughout peri-menopause, and beyond, if they listen to their bodies and be mindful of maintaining adequate dietary intake of key nutrients. It is important to recognise that both iron deficiency, thyroid function and hormonal changes can impact your ability to exercise.

Years of consistent exercise accumulate like pages in a book. As a mature you know your body very well. The pathway to success utilises your book of wisdom and skills. Mature athletes can benefit from greater recovery, individualized strength and conditioning and modified programs. Focussing on the balance between training intensity and volume will help you to achieve your desired goals.

If you suspect your symptoms are impacting on your quality of life and sport, it’s time to seek support to help you navigate the journey.

Blood serum pathology and functional tissue mineral testing can be a good starting point due to the critical role nutrients play in hormonal and thyroid function.

With the right self-care and a holistic approach to health, you can continue to achieve your life goals and physical challenges irrespective of hormonal changes.

About the Author: Kate Smyth is a Sports naturopath, nutritionist and female-centric running coach. She is the founder of the Athlete Sanctuary- a holistic healthcare clinic for athletes of all levels and sporting codes. Kate has a thirst for knowledge with two bachelor’s and a master’s degree under her belt. She has been involved in sports for many decades and competed for Australia in the Commonwealth Games and Olympic Games marathons with a personal best time of 2 hours 28 minutes. For more information visit www.https://



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