Thyroid hormones response in simulated laboratory sprint duathlon
Increased activity of the pituitary-thyroid axis, plays a role in adaptations to exercise. The aim of this study was to assess changes in thyroid hormones (TH) in a simulated laboratory competition of sprint duathlon. Eight duathletes trained males [mean (SD), age 24.8 (6.8) years, height 174.4 (6.8) cm, body mass 67.12 (8.1) kg] participate in this study. The duathletes performed two graded maximal exercise in random order, one on cycle-ergometer and other on a treadmill, to determine their VO2peak. Simulated laboratory competition was carried out during 20 min Run1, 40 min Bike and 12 min Run2 sectors. A blood sample was drawn to determine serum concentrations of TSH, T4, T3 and were analyzed by chemiluminiscence. A one-way analysis of variance (ANOVA) was used to analyze differences among sectors and Pearson correlation coefficients were calculated between TH and exercise intensity. Athletes perform a high intensity exercise reaching high mean values of aerobic power (89.6 ± 6.1, 85.1 ± 8.7 and 87.1 ± 6.9 of %VO2 in Run1, Bike and Run2 respectively). TSH shown differences between -30 min and Run2 (p< 0.05), and did not found changes in T3 and T4 during exercise (p>0.05). Significant inverse correlations between T3 (r= -0.86) and T4 (r= -0.86) and percent VO2 (p
Carrillo De Albornoz Gil, M. TSH and free thyroid hormones changes during incremental maximal aerobic exercise. [PhD thesis]. Málaga: University of Málaga, 2010.
Ciloglu, F., Peker, I., Pehlivan, A., Karacabey, K., Ilhan, N., Saygin, O., Et Al. Exercise intensity and its effects on thyroid hormones. Neuro Endocrinol Lett. 2005; 26(6):830-4.
Gullu, S., Altuntas, F., Dincer, I., Erol, C., Kamel, N. Effects of TSH-suppressive therapy on cardiac morphology and function: beneficial effects of the addition of beta-blockade on diastolic dysfunction. Eur J Endocrinol. 2004; 150:655-61. https://doi.org/10.1530/eje.0.1500655
Edwards, J.G., Bahl, J.J., Flink, I.L., Cheng, Y.S., Morkin, E. Thyroid hormone influences beta myosin heavy chain (beta MHC) expression. Biochem Biophys Res Commun. 1994; 199:1482-1488. https://doi.org/10.1006/bbrc.1994.1398
Koistinen, P., Martikkala, V., Karpakka, J., Vuolteenaho, O., Leppäluoto, J. The effects of moderate altitude on circulating thyroid hormones and thyrotropin in training athletes. J Sports Med Phys Fitness. 1996; 36:108-111.
Lucia, A., Hoyos, J., Pérez, M., Chicharro, J. Thyroid hormones may influence de slow component of VO2 in professional cyclist. Japan J Physiol. 2001; 51:239-242. https://doi.org/10.2170/jjphysiol.51.239
Miller, R.G., Boska, M.D., Moussavi, R.S., Carson, P.J., Weiner, M.W. Nuclear magnetic resonance studies of high energy phosphates and pH in human muscle fatigue. Comparison of aerobic and anaerobic exercise. J Clin Invest. 1988; 81:1190-1196. https://doi.org/10.1172/JCI113434
Pakarinen, A., Hakkinen, K., Alen, M. Serum thyroid hormones, thyrotropin and thyroxin binding globulin in elite athletes during very intense strength training in of one week. J Sports Med Phys Fitness. 1991; 31:142-6.
Ronconi, M., Alvero-Cruz, J.R. Heart rate and oxygen uptake responses in duathlon's sprint competition. Apunts Med Esport. 2011 (accepted).