Impact of preinduced quadriceps fatigue on exercise response in chronic obstructive pulmonary disease and healthy subjects

Abstract

Gagnon P, Saey D, Vivodtzev I, Laviolette L, Mainguy V, Milot J, Provencher S, Maltais F. Impact of preinduced quadriceps fatigue on exercise response in chronic obstructive pulmonary disease and healthy subjects. J Appl Physiol 107: 832-840, 2009. First published July 2, 2009 doi:10.1152/japplphysiol.91546.2008.-Exercise intolerance in chronic obstructive pulmonary disease (COPD) results from a complex interaction between central (ventilatory) and peripheral (limb muscles) components of exercise limitation. The purpose of this study was to evaluate the influence of quadriceps muscle fatigue on exercise tolerance and ventilatory response during constant-workrate cycling exercise testing (CWT) in patients with COPD and healthy subjects. Fifteen patients with COPD and nine age-matched healthy subjects performed, 7 days apart, two CWTs up to exhaustion at 80% of their predetermined maximal work capacity. In a randomized order, one test was performed with preinduced quadriceps fatigue and the other in a fresh state. Quadriceps fatigue was produced by electrostimulation-induced contractions and quantified by maximal voluntary contraction and potentiated twitch force (TwQ pot). Endurance time and ventilatory response during CWT were compared between fatigued and fresh state. Endurance time significantly decreased in the fatigued state compared with the fresh condition in COPD (356 Ϯ 69 s vs. 294 Ϯ 45 s, P Ͻ 0.05) and controls (450 Ϯ 74 s vs. 340 Ϯ 45 s, P Ͻ 0.05). Controls showed significantly higher ventilation and end-exercise dyspnea scores in the fatigued condition, whereas, in COPD, fatigue did not influence ventilation or dyspnea during exercise. The degree of ventilatory limitation, as expressed by the V E/ maximum voluntary ventilation ratio, was similar in both conditions in patients with COPD. We conclude that it is possible to induce quadriceps fatigue by local electrostimulation-induced contractions. Our findings demonstrate that peripheral muscle fatigue is an additional important factor, besides intense dyspnea, that limits exercise tolerance in COPD. quadriceps muscle fatigue; exercise tolerance; ventilatory response; electrostimulation EXERCISE INTOLERANCE IS ASSOCIATED with poor quality of life (16) and increased mortality (28)

An Official American Thoracic Society/European Respiratory Society Statement: Update on Limb Muscle Dysfunction in Chronic Obstructive Pulmonary Disease

“…This concept is in line with the notion that the central nervous system integrates information originating from the limb muscles to determine the duration of exercise and the degree of muscle fatigue (294,297). Preinduction of muscle fatigue by neuromuscular electrical stimulation contributed to limitation of exercise tolerance in patients with COPD (298). Spinal anesthesia, presumably blocking group III/IV sensory afferent signals from the lower limb muscles, was shown to improve exercise duration to constant work rate exercise in patients with COPD (295).…”

Impact of pulmonary system limitations on locomotor muscle fatigue in patients with COPD

“…Most relevant to the present findings, peripheral locomotor muscle fatigue was induced in patients with COPD via electrical motor nerve stimulation just before the start of a constant-load bicycle performance test. This preexercise quadriceps fatigue significantly reduced the exercise time to voluntary exhaustion (21). Thus exercise-induced limb fatigue by itself appears to exert a significant effect on endurance exercise performance in healthy subjects and patients with COPD.…”

“…However, substantial exercise-induced locomotor muscle fatigue also occurs in many of these patients (34, 39 -41), and their susceptibility to peripheral muscle fatigue is greater than in age-matched healthy control subjects exercising at the same work rate (39,40). Peripheral muscle fatigue has been shown to play an important feedback role in limiting central motor output to the locomotor muscle (5,6,8,9), and inducing preexercise limb fatigue reduces endurance exercise performance in healthy individuals (5) and in COPD (21).…”

Effect of pulmonary TNF-α overexpression on mouse isolated skeletal muscle function

“…Chronic obstructive pulmonary disease (COPD), which is associated with reduced exercise capacity and quality of life, can result in significant muscle wasting and atrophy (28). Peripheral muscle fatigue can often significantly limit exercise tolerance in COPD patients (10). It has been speculated that the sustained pulmonary inflammation may have remote effects on peripheral tissues via chronic inflammatory mediators released into the circulation in COPD patients (3,16).…”