Disfunção muscular periférica em DPOC: membros inferiores versus membros superiores

Abstract

In patients with COPD, the degree of functional impairment appears to differ between the upper and lower limbs. Significant dyspnea and fatigue have been reported by these patients when performing tasks with unsupported upper limbs and two mechanisms have been proposed to explain this fact: neuromechanical dysfunction of respiratory muscles; and changes in lung volume during such activities. The neuromechanical dysfunction seen in COPD patients during this type of exercise is related to changes in the breathing pattern, as well as to the simultaneity of afferent and efferent muscle stimuli, resulting in respiratory muscle asynchrony. In addition, the increased ventilation during upper limb exercise in patients with COPD leads to dynamic hyperinflation at different workloads. During lower limb exercises, the strength and endurance of the quadriceps muscle is lower in COPD patients than in healthy subjects. This could by explained by abnormal muscle metabolism (decreased aerobic capacity), dependence on glycolytic metabolism, and rapid accumulation of lactate during exercise. In comparison with lower limb exercises, upper limb exercises result in higher metabolic and ventilatory demands, as well as in a more intense sensation of dyspnea and greater fatigue. Because there are differences between the upper and lower limb muscles in terms of the morphological and functional adaptations in COPD patients, specific protocols for strength training and endurance should be developed and tested for the corresponding muscle groups.Keywords: Pulmonary disease, chronic obstructive; Muscle fatigue; Upper extremity; Lower extremity. ResumoO prejuízo funcional parece diferir entre membros superiores e membros inferiores de pacientes com DPOC. Dois possíveis mecanismos explicam os sintomas importantes de dispneia e fadiga relatados pelos pacientes ao executar tarefas com membros superiores não sustentados: a disfunção neuromecânica dos músculos respiratórios e a alteração dos volumes pulmonares durante as atividades realizadas com membros superiores. A disfunção neuromecânica está relacionada à alteração do padrão respiratório e à simultaneidade de estímulos aferentes e eferentes musculares, o que causaria a dissincronia na ação dos músculos respiratórios em pacientes com DPOC durante esse tipo de exercício. Adicionalmente, o aumento da ventilação durante os exercícios com membros superiores em pacientes com DPOC induz à hiperinsuflação dinâmica em diferentes cargas de trabalho. Nos membros inferiores, há redução da força e da endurance muscular do quadríceps femoral nos pacientes com DPOC comparados a indivíduos saudáveis. Uma explicação para essas reduções é a anormalidade no metabolismo muscular (diminuição da capacidade aeróbia), a dependência do metabolismo glicolítico e o acúmulo rápido de lactato durante o exercício. Quando contrastadas as atividades de membros superiores e membros inferiores, os exercícios com membros superiores resultam em maior demanda metabólica e ventilatória com mais intensa sensação de dispne...

Mid-arm and calf circumferences are stronger mortality predictors than body mass index for patients with chronic obstructive pulmonary disease

“…The degree of functional impairment between the upper and lower limbs differs among patients with COPD. Lower limb muscles appear to be associated with muscle endurance and daily functional performance, whereas upper limb muscles have been correlated with both physical and pulmonary functional indicators 26. Raftery (1995) suggested that a lower BIC value of 2–6 is a positive evidence for a model 20.…”

Responsividade do teste do degrau de seis minutos a um programa de treinamento físico em pacientes com DPOC

“…(2) However, Dal Corso et al (1) and Swinburn et al (3) reported that step climbing involves working against gravity and the use of muscle groups that are not frequently used during activities of daily living, which produces physiological responses that are different from those of the walk test, making the metabolic and ventilatory demands of step climbing more intense. In addition, it should be borne in mind that the leg muscles in patients with COPD are impaired in terms of strength and endurance because of a reduction in muscle mass and aerobic capacity, (4) compromising performance. For this reason, it is important that leg muscle exercises be performed to improve the functional performance of these patients.…”

Upper-Body Resistance Training and Self-Efficacy Enhancement in COPD

“…Resistance training typically includes a combination of resistance exercises for upper-body, lower-body and trunk muscles with an emphasis on lower-body resistance training [1,2]. Little is known about the unique contribution of upper-body resistance training to outcomes such as symptoms and functional performance [3] and about long term maintenance after completion of a structured program of resistance training in people with COPD.…”

“…There are differences in the morphological adaptations to COPD between the muscles of the upper body and lower body [3]. Greater fatigability has been observed for the upper extremity muscles.…”