title: Home-based aerobic exercise training improves skeletal muscle oxidative metabolism in patients with metabolic myopathies.
abstract: Aerobic training can be effective in patients with mitochondrial myopathies (MM) and McArdle's disease (McA). The aim of the study was to use noninvasive functional evaluation methods, specifically aimed at skeletal muscle oxidative metabolism, to evaluate the effects of an aerobic exercise training (cycle ergometer, 12 wk, 4 days/wk, ∼65-70% of maximal heart rate) in 6 MM and 7 McA. Oxygen uptake and skeletal muscle vastus lateralis fractional O2 extraction by near-infrared spectroscopy were assessed during incremental and low-intensity constant work rate (CWR) exercises before (BEFORE) and at the end (AFTER) of training. Peak O2 uptake increased significantly with training both in MM [14.7 ± 1.2 vs. 17.6 ± 1.4 ml·kg(-1)·min(-1) (mean ± SD)] and in McA (18.5 ± 1.8 ml·kg(-1)·min(-1) vs. 21.6 ± 1.9). Peak skeletal muscle fractional O2 extraction increased with training both in MM (22.0 ± 6.7 vs. 32.6 ± 5.9%) and in McA (18.5 ± 6.2 vs. 37.2 ± 7.2%). During low-intensity CWR in both MM and McA: V̇o2 kinetics became faster in AFTER, but only in the patients with slow V̇o2 kinetics in BEFORE; the transient overshoot in fractional O2 extraction kinetics disappeared. The level of habitual physical activity was not higher 3 mo after training (FOLLOW-UP vs. PRE). In MM and McA patients a home-based aerobic training program significantly attenuated the impairment of skeletal muscle oxidative metabolism and improved variables associated with exercise tolerance. Our findings indicate that in MM and McA patients near-infrared spectroscopy and V̇o2 kinetics can effectively detect the functional improvements obtained by training.
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council, Segrate, Italy; Department of Medical and Biological Sciences, University of Udine, Udine, Italy simone.porcelli@ibfm.cnr.it.
authors.forename: Simone
authors.identifier: 0000-0002-9494-0858
authors.initials: S
authors.lastname: Porcelli
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council, Segrate, Italy;
authors.forename: Mauro
authors.initials: M
authors.lastname: Marzorati
authors.affiliation: IRCCS Istituto Neurologico "Carlo Besta" Foundation, Milan, Italy; and.
authors.forename: Lucia
authors.initials: L
authors.lastname: Morandi
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council, Segrate, Italy; Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Grassi
mesh_terms: D000328:Adult; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000503:physiopathology* / Q000628:therapy*; D006699:Home Care Services; D006801:Humans; D008297:Male; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000503:physiopathology* / Q000628:therapy*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D016896:Treatment Outcome
chemical_list: D010100:Oxygen
keywords: McArdle's disease; V̇o2 kinetics; mitochondrial myopathies; near-infrared spectroscopy