1. Archive
2. Vol.51, No.2

Thyroid Hormones May Influence the Slow Component of VO₂ in Professional Cyclists

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 VO₂ slow component (VO₂) 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@o@_{2 max} (or ∼400 W). Plasma concentrations of T₃ and T₄ were inversely correlated (p<0.05) with VO₂ (r−0.72 and rr−0.66, respectively), suggesting, at least partly, and association between thyroid basal function and the VO₂ slow component of euthyroid elite endurance athletes during constant-load intense exercise.

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