Thyroid Therapy or Dysfunction in Athletes: Is it Time to Revisit the Clinical Practice Guidelines?

Area of Science:

• Sports Medicine
• Endocrinology
• Anti-Doping

Background:

• Controversy exists regarding hypothyroidism treatment in elite athletes.
• The World Anti-Doping Agency has not banned thyroid medication use.
• Current scientific evidence does not link thyroid medication to performance enhancement.

Purpose of the Study:

• To review the current understanding of hypothyroidism in elite athletes.
• To discuss diagnostic challenges and performance-enhancing potential of thyroid medication.
• To highlight the need for further research in this area.

Main Methods:

• Review of current literature on hypothyroidism, athletic performance, and anti-doping regulations.
• Analysis of diagnostic criteria for hypothyroidism, including thyroid-stimulating hormone (TSH), free T4, and thyrotropin-releasing hormone (TRH) stimulation tests.
• Examination of the physiological effects of hypothyroidism on athletic function.

Main Results:

• Hypothyroidism can impair cardiopulmonary function and cause symptoms like fatigue and muscle stiffness.
• Symptoms of hypothyroidism overlap with those of overtraining syndrome, complicating diagnosis.
• No established association between training status and hypothyroidism has been identified.

Conclusions:

• Clear diagnostic criteria for hypothyroidism in athletes are lacking.
• Further research is needed to define hypothyroidism, assess performance-enhancing effects of thyroid medication, and explore training-induced hypothyroidism.
• Current evidence does not support the use of thyroid medication for performance enhancement in athletes.