Exercise and Thyroid Function

Ylli, D.; Klubo-Gwiezdzinska, J.; Wartofsky, L. ✉

Angol nyelvű Tudományos Könyvfejezet (Könyvrészlet)
    Thyroid hormone receptors are present in virtually every tissue in the body, thereby permitting an important physiologic role for the thyroid hormones, thyroxine (T4), and triiodothyronine (T3). The aim of this chapter is to describe the effects of thyroid function on exercise tolerance with a special focus on cardiovascular, pulmonary, and skeletal muscle function as well as to describe the changes in the pituitary–thyroid axis induced by exercise. Hypothyroidism is associated with impaired left ventricular diastolic function during exercise, blunted vasodilatation secondary to reduced endothelium-dependent vasodilatation, reduced pulmonary forced vital capacity and tidal volume at the anaerobic threshold, and, finally, impaired oxidative phosphorylation in mitochondria of skeletal muscle. Hyperthyroidism is associated with increased left ventricular ejection fraction (LVEF) at rest, lack of an increase or even a drop in LVEF with exercise, increased oxygen demand, low efficiency of cardiopulmonary function, respiratory muscle weakness, and impaired work capacity. Physical activity affects the pituitary–thyroid axis and the peripheral metabolism of thyroxine. Factors that mitigate alterations in thyroid hormone economy with exercise include age, baseline fitness, nutritional status, ambient temperature, altitude, as well as the time, intensity, and type of exercise performed. The most consistent finding is that reverse T3 tends to increase with exercise. This may reflect an adaptive mechanism aimed at more efficient energy expenditure. © 2020, Springer Nature Switzerland AG.
    Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSLMásolásNyomtatás
    2021-05-07 13:03