OBJETIVE: The evaluation, by exercise stress testing, of the cardiorespiratory effects of pyridostigmine (PYR), a reversible acetylcholinesterase inhibitor. METHODS: A double-blind, randomized, cross-over, placebo-controlled comparison of hemodynamic and ventilation variables of 10 healthy subjects who underwent three exercise stress tests (the first for adaptation and determination of tolerance to exercise, the other two after administration of placebo or 45mg of PYR). RESULTS: Heart rate at rest was: 68±3 vs 68±3bpm before and after placebo, respectively (P=0.38); 70±2 vs 59±2bpm, before and after pyridostigmine, respectively (P<0.01). During exercise, relative to placebo: a significantly lower heart rate after PYR at, respectively, 20% (P=0.02), 40% (P=0.03), 80% (P=0.05) and 100% (P=0.02) of peak effort was observed. No significant differences were observed in arterial blood pressure, oxygen consumption at submaximal and maximal effort, exercise duration, respiratory ratio, CO2 production, ventilation threshold, minute ventilation, and oxygen pulse. CONCLUSION: Pyridostigmine, at a dose of 45mg, decreases heart rate at rest and during exercise, with minimal side effects and without interfering with exercise tolerance and ventilation variables.

O hipertireoidismo está associado a uma fraqueza muscular generalizada que é parte da manifestação clínica inicial de cerca de 80% dos pacientes. A recuperação da performance muscular esquelética durante o tratamento do hipertireoidismo depende tanto do aumento da massa muscular quanto da melhoria da função intrínseca da musculatura esquelética. Por outro lado, o treinamento contra resistência aumenta a força e a endurance muscular em diferentes grupos de indivíduos. O objetivo do presente trabalho foi avaliar o efeito deste tipo de treinamento sobre a recuperação da função muscular esquelética de pacientes portadores de hipertireoidismo. Os pacientes, atendidos no ambulatório de endocrinologia, diagnosticados clínica e laboratorialmente com doença de Graves, foram submetidos, antes do tratamento e quatro meses após, a medidas antropométricas e testes de força máxima e endurance musculares (sustentando 30% da carga máxima) de quatro movimentos [handgrip esquerdo (HE) e direito (HD), legpress (LEG), flexão plantar de tornozelo (FPT) e supino reto (SR)]. Após a avaliação inicial, os pacientes foram divididos em dois grupos: 1) controle (GC - tratamento medicamentoso) e 2) treinamento (GT - acrescentado treinamento contra resistência individualizado 2X/semana). Os resultados (GC, n = 3; GT, n = 4; todas do sexo feminino) mostram: <img src="/img/revistas/rbme/v7n1/a04tab01.gif"> Os autores concluem que o treinamento contra resistência parece favorecer aumento da massa e da performance muscular esquelética em pacientes com hipertireoidismo.

Hyperthyroidism is associated with a general muscle weakness, which is part of the initial clinical manifestation of about 80% of patients. The recovery of skeletal muscle performance during hyperthyroidism treatment depends on both greater muscle mass and improved muscle function. Strength training is an effective method to improve muscle strength and endurance. The purpose of this study was to evaluate the effect of this type of training on the recovery of the skeletal muscle function of patients with hyperthyroidism. Patients referred to the Endocrinology Out-Patient Clinic with clinical diagnosis and laboratory confirmation of Grave's disease were submitted, before the treatment and 4 months later, to anthropometric measurements and determination of maximal static strength and endurance (sustaining 30% of the maximal force) of four movements [left handgrip (LH), right handgrip (RH), legpress (LEG), ankle plantar flexion (APF) and supine benchpress (SP)]. After the first evaluation, the patients were divided into two groups: 1) control (CG- drug treatment) and 2) training (TG- added individualized strength training twice a week). Results (CG, n=3; TG, n=4; all women) showed: <img src="/img/revistas/rbme/v7n1/a04tab02.gif"> The authors concluded that strength training seems to favor an increase in skeletal muscle mass and performance in patients with hyperthyroidism.