Serviço de Endocrinologia, Hospital Universitário Clementino Fraga Filho, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Brasil.
Braz J Med Biol Res. 2010 Nov;43(11):1095-101. doi: 10.1590/s0100-879x2010007500116. Epub 2010 Oct 29.
Subclinical hypothyroidism (SH) patients present cardiopulmonary, vascular and muscle dysfunction, but there is no consensus about the benefits of levothyroxine (L-T₄) intervention on cardiopulmonary performance during exercise. The aim of the present study was to investigate the effects of L-T₄ on cardiopulmonary exercise reserve and recovery in SH patients. Twenty-three SH women, 44 (40-50) years old, were submitted to two ergospirometry tests, with an interval of 6 months of normalization of thyroid-stimulating hormone (TSH) levels (L-T₄ replacement group) or simple observation (TSH = 6.90 μIU/mL; L-T₄ = 1.02 ng/dL). Patients with TSH >10 μIU/mL were excluded from the study to assure that they would receive treatment in this later stage of SH. Twenty 30- to 57-year-old women with no thyroid dysfunction (TSH = 1.38 μIU/mL; L-T₄ = 1.18 ng/dL) were also evaluated. At baseline, lower values of gas exchange ratio reserve (0.24 vs 0.30; P < 0.05) were found for SH patients. The treated group presented greater variation than the untreated group for pulmonary ventilation reserve (20.45 to 21.60 L/min; median variation = 5.2 vs 25.09 to 22.45 L/min; median variation = -4.75, respectively) and for gas exchange ratio reserve (0.19 to 0.27; median variation = 0.06 vs 0.28 to 0.18; median variation = -0.08, respectively). There were no relevant differences in cardiopulmonary recovery for either group at baseline or after follow-up. In the sample studied, L-T₄ replacement improved exercise cardiopulmonary reserve, but no modification was found in recovery performance after exercise during this period of analysis.
亚临床甲状腺功能减退症（SH）患者存在心肺、血管和肌肉功能障碍，但对于左甲状腺素（L-T₄）干预对运动时心肺功能的益处尚无共识。本研究旨在探讨 L-T₄对 SH 患者心肺运动储备和恢复的影响。23 名 44（40-50）岁的 SH 女性患者接受了两次运动心肺功能测试，两次测试间隔 6 个月，以恢复甲状腺刺激激素（TSH）水平的正常化（L-T₄ 替代组）或单纯观察（TSH = 6.90 μIU/mL；L-T₄ = 1.02 ng/dL）。为了确保这些患者在 SH 的后期阶段得到治疗，排除了 TSH >10 μIU/mL 的患者。还评估了 20 名 30-57 岁无甲状腺功能障碍的女性（TSH = 1.38 μIU/mL；L-T₄ = 1.18 ng/dL）。在基线时，SH 患者的气体交换比储备值较低（0.24 比 0.30；P <0.05）。与未治疗组相比，治疗组的肺通气储备变化更大（20.45 至 21.60 L/min；中位数变化= 5.2 比 25.09 至 22.45 L/min；中位数变化= -4.75），气体交换比储备变化更大（0.19 至 0.27；中位数变化= 0.06 比 0.28 至 0.18；中位数变化= -0.08）。两组在基线或随访后心肺恢复均无明显差异。在研究样本中，L-T₄ 替代治疗改善了运动心肺储备，但在分析期间未发现运动后恢复性能的改变。
