Blood Fuel Metabolites at Rest and during Exercise in Patients with Advanced Chronic Obstructive Pulmonary Disease with and without Chronic Respiratory Failure

144

This study tested the effect of two methods of training, one individualized at the heart rate corresponding to the gas exchange threshold (GET) and the other at the heart rate corresponding to 50% of maximal heart rate reserve, on maximal and submaximal cardiorespiratory response in 24 patients with chronic airway limitation (CAL).The patients were randomly assigned to either the individualized training group (IT; n=12) or the standardized training group (ST; n=12). The training programme consisted of 4 weeks of stationary bicycle exercise, 5 days·week -1 .Before reconditioning began, the target level based on heart rate was not significantly different between groups (109±4 versus 110±3 beats·min -1 , in IT and ST, respectively). Post-training, a significant increase in symptom-limited oxygen uptake (V 'O 2 ,sl) and maximal O 2 pulse was found in IT, whereas ST exhibited no significant change. In each group, GET was statistically increased in much the same way as V 'O 2 ,sl, with a higher increase in IT (p<0.01) than ST (p<0.05). Nevertheless, IT exhibited a concomitant and gradual decrease in minute ventilation (V 'E), carbon dioxide production (V 'CO 2 ), and venous lactate concentration ([La]), whereas ST presented no significant change in these parameters (intergroup p<0.01). Breathing pattern was also altered after IT, at the same metabolic level and at the same ventilation level (intergroup p<0.05). Cardiac responses were modified in the two groups. At the same metabolic level, a significantly lower cardiac frequency was found both for IT and ST (intragroup p<0.05 after training). In contrast, the increase in O 2 pulse was only significantly higher in IT after training.These data show the greater efficiency of an individualized training protocol based on determination of gas exchange threshold as compared to a standardized protocol, in improving exercise performance, when applied to a patient group. Despite an apparently similar target training level, the individualized method clearly optimized the physiological training effects in patients with chronic airway limitation and, more particularly, decreased their ventilatory requirement.

Section: Training Effectssupporting

confidence: 89%

Comparison of two training programmes in chronic airway limitation patients: standardized versus individualized protocols

Vallet¹,

Ahmaidi²,

Serres³

et al. 1997

144

“…In the patient population, COPD has been demonstrated to induce variable alterations in fibre composition of peripheral skeletal muscles. Similar to the present investigation, HUGHES et al [10] and JAKOBSSON et al [25] demonstrated no differences in fibre composition of vastus lateralis muscle biopsies from COPD patients, and SATO et al [11] found no difference in fibre composition in biceps brachii muscle biopsies. In contrast, other investigators [4,6,7] have reported that COPD patients have a lower proportion of type I fibres and an elevation in the per cent of type II fibres in the vastus lateralis muscle.…”

Section: Potential Mechanismssupporting

confidence: 89%

Differential effects of emphysema on skeletal muscle fibre atrophy in hamsters

Mattson

Delp²,

Poole³

2004

Patients afflicted with emphysema demonstrate altered peripheral skeletal muscle fibre composition and atrophy. It is unknown whether these alterations are general to all skeletal muscles independent of function, phenotype or oxidative capacity. Therefore, the purpose of this investigation was to determine whether emphysema induces alterations in muscle fibre composition or atrophy in respiratory and locomotory muscles with diverse fibre types and metabolic profiles.Fibre composition and cross-sectional area were measured in selected hindlimb muscles and diaphragm of hamsters following saline (control, n=7) or elastase (emphysema, n=15) instillation.Excised lung volume increased 145% with emphysema. Fibre composition was largely unaltered, with the exception of a 13% reduction in IIB fibres in the tibialis anterior muscle of emphysema animals. Type I fibre size was also mainly unaltered, except for a diminished cross-sectional area in plantaris muscle. However, fibre cross-sectional area of fast-twitch types IIA, IIX and/or IIB fibres was reduced in the caudal biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius and plantaris muscles of emphysema animals. In contrast, there was a trend for emphysema to increase the cross-sectional area of type IIA fibres in the diaphragm.These data demonstrate that emphysema-induced atrophy primarily affects locomotory muscles, independent of phenotype or oxidative capacity.

“…Contractile strength is reduced [2] and energetic and oxidative metabolism are impaired [3][4][5]. Fibre-type composition is also altered, with a decrease in the proportion of fatigue-resistant slow fibres [3,6]. Muscle alterations are potentially important in determining both the low tolerance to exercise [5] and the improvement after physical training [7,8].…”

mentioning

confidence: 99%

Fibre types in skeletal muscles of chronic obstructive pulmonary disease patients related to respiratory function and exercise tolerance

Satta¹,

Migliori²,

Spanevello³

et al. 1997

136

F Fi ib br re e t ty yp pe es s iin n s sk ke el le et ta al l m mu us sc cl le es s o of f c ch hr ro on ni ic c o ob bs st tr ru uc ct ti iv ve e p pu ul lm mo on na ar ry y d di is se ea as se e p pa at ti ie en nt ts s r re el la at te ed d t to o r re es sp pi ir ra at to or ry y f fu un nc ct ti io on n a an nd d e ex xe er rc ci is se e t to ol le er ra an nc ce e A group of 22 COPD patients and 10 healthy control subjects were studied. In COPD patients, vital capacity (VC) and forced expiratory volume in one second (FEV1) were reduced to 79% and 51%, respectively. Diffusion indices (transfer factor of the lung for carbon monoxide (TL,CO) and carbon monoxide transfer coefficient (KCO)) were also reduced. Arterial oxygen tension (Pa,O 2 ) was normal or slightly altered. A maximal exercise test was performed and anaerobic threshold was calculated. Muscle samples from vastus lateralis were obtained by needle biopsy. Myosin heavy chain (MHC) and light chain (MLC) isoforms were separated by gel electrophoresis and quantified by densitometry. MHC isoforms were considered as molecular markers of fibre types.The proportion of the fast MHC-2B isoform was increased in COPD patients. TL,CO, KCO, VC and FEV1 were positively correlated with slow MHC isoform content. TL,CO and KCO were also negatively correlated with the content of the fast MHC-2B isoform. No correlation was found between exercise parameters and MHC isoform composition. The co-ordinated expression between MHC and MLC isoforms was altered in COPD patients.We conclude that reduced oxygen availability, probably in combination with muscle disuse, may determine muscle alterations in chronic obstructive pulmonary disease patients. The altered correlations between myosin heavy chain and light chain isoforms suggest that co-ordinated protein expression is lost in chronic obstructive pulmonary disease muscles. Eur Respir J 1997; 10: 2853-2860 Patients with chronic obstructive pulmonary disease (COPD) are characterized by poor quality of life and various degrees of limitation in their daily activity, mainly due to breathlessness. They are often self-limiting their level of activity into a downward spiral leading to further inactivity and muscle deconditioning. Exercise tolerance of COPD patients is determined by the level of ventilation that they can reach. Even at a rather low work rate the increase in ventilatory response and blood lactate concentration are higher than in normal subjects.Rehabilitation of COPD patients involves general exercise reconditioning. This is suggested as the best approach to the rehabilitation of COPD patients, and is usually performed by training large muscles of the lower and, less frequently, upper limbs [1]. The mechanisms underlying the improvement of the performance after general training in COPD subjects are still unclear.There is evidence that skeletal muscle function and structure are altered in COPD patients. Contractile strength is reduced [2] and energetic and oxidative metabolism are impaired [3][4][5]. Fibre-type compos...