What role does TSH play in Sport?

TSH (thyroid-stimulating hormone) does not directly enhance athletic performance but reflects thyroid status, which regulates metabolism, energy expenditure, and muscle recovery. In sports, overtraining can suppress the thyroid axis, leading to low T3 with normal TSH (euthyroid sick syndrome). Evidence for a direct role of TSH in sport is moderate: observational studies link thyroid dysfunction to reduced exercise capacity, but interventional data are lacking. MyBody-X tests include TSH as a standard blood marker, but results are for informational use only, not medical diagnosis. Abnormal TSH should prompt a medical evaluation, as untreated thyroid disorders can impair performance and recovery.