A Healthy Thyroid is a Healthy Heart - Why Your Heart Needs a Health Thyroid


If you have a thyroid condition or a heart condition a hormone made by your thyroid gland called “T3" might just be the most important number you need to know.  Researchers claim T3 is a stronger predictor of death and cardiovascular mortality than age, fats or a poor functioning heart muscle!

Heart cells can only use a a form of thyroid hormone that is biologically active called T3. Unfortunately in the US, UK and in Australia T3 is not commonly tested nor prescribed.  

The lack of knowledge about T3 means if you get too much or too little of this hormone in your heart it may just have a fatal outcome. I call this your ‘Goldilocks number’. Like Goldilocks your heart doesn’t like to be too hot / too fast or too cold / too slow it wants to be just right!

This conversation is not just relevant for those with a known thyroid condition. A review of congestive heart failure found approximately 30% of these patients had low T3 even though they had not been diagnosed with a thyroid condition.  Plus the decreased T3 level was proportional to the severity of the heart disease.

In the US, UK and Australia when a thyroid problem is diagnosed whether it be hyperthyroidism (typically caused by Graves’ diseases) or hypothyroidism (typically caused by Hashimoto’s thyroiditis) rarely is T3 monitored or medicated.

When hyperthyroid and in Graves’ disease people can develop:  heart palpitations, fast heart beat, exercise intolerance, breathlessness, blood pressure changes and atrial fibrillation.  Cardiac output may be increased by 50% to 300% over that of healthy people. The combined effect of increases in resting heart rate may lead to enlarged hearts and high risk of heart failure. 

When hypothyroid and in Hashimoto’s thyroiditis people commonly develop: slow heart beat, high blood pressure, cold intolerance, and fatigue. Unfortunately these patients also have a reduced ability to process fats and a tendency to high cholesterol levels and atherosclerosis - a symptom picture commonly associated with serious and life threatening heart conditions.

Do you know your Goldilocks number?

In health,

Sonia x 


Klein, I., & Danzi, S. (2007). Thyroid disease and the heart. Circulation, 116(15), 1725-1735.

Sonia McNaughton