Skeletal muscle reoxygenation after high-intensity exercise in mitochondrial myopathy
| Autor: | Eloara V.M. Ferreira, Ethiane Meda, Ana Cristina Gimenes, Daniela M. Bravo, Luiz Eduardo Nery, J. Alberto Neder, Rubia B. Nascimento, Ana Cristina B. Siqueira |
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| Rok vydání: | 2010 |
| Předmět: |
Adult
Male Muscle metabolism Pathology medicine.medical_specialty Physiology Oxygen Consumption Mitochondrial myopathy Physiology (medical) medicine Humans Orthopedics and Sports Medicine In patient Muscle Skeletal Exercise Physics Spectroscopy Near-Infrared Pulmonary Gas Exchange High intensity Public Health Environmental and Occupational Health Hemodynamics Skeletal muscle Mitochondrial Myopathies General Medicine Human physiology medicine.disease Oxygen uptake Crystallography Patient population Kinetics medicine.anatomical_structure Case-Control Studies Exercise Test Female |
| Zdroj: | European journal of applied physiology. 112(5) |
| ISSN: | 1439-6327 |
| Popis: | This study addressed whether O2 delivery during recovery from high-intensity, supra-gas exchange threshold exercise would be matched to O2 utilization at the microvascular level in patients with mitochondrial myopathy (MM). Off-exercise kinetics of (1) pulmonary O2 uptake $$ (\dot{V}{\text{O}}_{2} {\text{p}}), $$ (2) an index of fractional O2 extraction by near-infrared spectroscopy (Δ[deoxy-Hb + Mb]) in the vastus lateralis and (3) cardiac output (Q T ′ ) by impedance cardiography were assessed in 12 patients with biopsy-proven MM (chronic progressive external ophthalmoplegia) and 12 age- and gender-matched controls. Kinetics of $$ \dot{V}{\text{O}}_{2} {\text{p}} $$ were significantly slower in patients than controls (τ = 53.8 ± 16.5 vs. 38.8 ± 7.6 s, respectively; p 0.05) being typically slower than $$ \dot{V}{\text{O}}_{2} {\text{p}} $$ in both groups. Importantly, Δ[deoxy-Hb + Mb] dynamics (MRT) were equal to, or faster than, $$ \tau \dot{V}{\text{O}}_{2} {\text{p}} $$ in patients and controls, respectively. In fact, there were no between-group differences in $$ \tau \dot{V}{\text{O}}_{2} {\text{p}} $$ /MRTΔ[deoxy-Hb + Mb] (1.1 ± 0.4 vs. 1.0 ± 0.2, p > 0.05) thereby indicating similar rates of microvascular O2 delivery. These data indicate that the slower rate of recovery of muscle metabolism after high-intensity exercise is not related to impaired microvascular O2 delivery in patients with MM. This phenomenon, therefore, seems to reflect the intra-myocyte abnormalities that characterize this patient population. |
| Databáze: | OpenAIRE |
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