Abstract
We analyzed the relationship between the plasma concentrations of several hormones (testosterone [T], follicle-stimulating [FSH] and luteinizing hormone [LH], cortisol [C], 3,5,3′-triiodothyronine [T3], thyroxine [T4], and thyrotrophin [TSH]) and the magnitude of the V˙O2 slow component (δV˙O2) in a group of nine professional road cyclists (26±2 years). The resting levels of the aforementioned hormones were determined before the subjects performed a 20-min cycle ergometer test at ~80% of V˙O2 max (or ~400 W). Plasma concentrations of T3 and T4 were inversely correlated (p<0.05) with δV˙O2 (r=−0.72 and r=−0.66, respectively), suggesting, at least partly, and association between thyroid basal function and the V˙O2 slow component of euthyroid elite endurance athletes during constant-load intense exercise.
