Effectiveness of exercise training in patients with COPD: the role of muscle fatigue

Abstract

The improvement in exercise performance in response to exercise training varies greatly from one patient with chronic obstructive pulmonary disease to another. It is possible that in a portion of patients the muscle stimulus applied during exercise training is insufficient to elicit training effects. We investigated whether patients presenting quadriceps contractile fatigue after training have more favourable effects of a rehabilitation programme.46 patients followed a 3-month high-intensity exercise training programme. Exercise capacity, quadriceps force and quality of life were measured before and after the programme. Exercise training-induced quadriceps contractile fatigue was assessed after 1 month of rehabilitation with magnetic stimulation. A fall in quadriceps force of o15%, 15 min after training was considered as significant fatigue.29 (63%) out of 46 patients developed significant fatigue. Patients with fatigue had a higher increase in 6-min walk distance (median (interquartile range) 57 (47-103) m versus 17 (-7-46) m; p50.0023) and Chronic Respiratory Disease Questionnaire score (mean¡SD 22¡12 points versus 14¡12 points; p50.028) after the training programme compared with patients without fatigue. Improvements in quadriceps force and maximal exercise capacity were similar in both subgroups.Patients who develop quadriceps contractile fatigue during exercise training show greater training effects in terms of functional exercise capacity and health-related quality of life.

Physical activity, nutritional status and systemic inflammation in COPD

“…The corollary of this is, therefore, that ''non-fatiguers'' should benefit less from rehabilitation than ''fatiguers''. This is, however, not completely true, because it has recently been shown that exercise tolerance has improved after rehabilitation even in ''non-fatiguers'' [75]. The picture is very complex, and may involve several other contributing factors such as exertional dyspnoea, ventilatory limitation/constraint, dynamic lung hyperinflation and lack of motivation.…”

“…For example, high intensity or longer duration programmes have been associated with a larger response compared with less intense or shorter programmes [73,74]. Patients who present with significant contractile fatigue after an exercise training session also show more pronounced training effects [75]. Some COPD patients with pronounced muscle wasting (cachectic patients) seem to be more prone to the effect of oxidative stress and inflammation at the muscle level [51,62,63,76].…”

“…The initial mechanisms of exercise limitation appear to affect the exercise outcome to pulmonary rehabilitation [81]. Recent information suggests that COPD patients who develop quadriceps contractile fatigue during exercise training show greater training effects in terms of functional exercise capacity and health-related quality of life [75]. The typical clinical portrait of a patient with COPD ''responder'' to exercise training looks like someone whose poor exercise tolerance is related mainly to weak skeletal muscles (i.e.…”

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

“…Together, these studies highlight the potential contribution of the distal limb muscle fatigue in daily physical activities in patients with COPD. The occurrence of muscle fatigue may also modulate the response to exercise training programs, as illustrated by the observation that patients with COPD developing quadriceps fatigue during exercise training have larger training effects compared with those who did not fatigue during the same session (299).…”

Pulmonary rehabilitation and COPD: is nonlinear exercise better?

“…Firstly, one of the main reasons for using NLPE training, according to Klijn and colleagues, is the possibility of avoiding overtraining and, consequently, the development of muscle fatigue, optimizing the gains in muscle endurance and strength. However, Burtin and colleagues [18] recently suggested that developing fatigue during exercise training was associated with better outcomes in patients with COPD. Then, the role of muscle fatigue in the rehabilitation of patients with COPD still has to be elucidated.…”