Home-based aerobic exercise training improves skeletal muscle oxidative metabolism in patients with metabolic myopathies

摘要

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, similar to 65-70% of maximal heart rate) in 6 MM and 7 McA. Oxygen uptake and skeletal muscle vastus lateralis fractional O-2 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 O-2 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: (V) over dotO(2) kinetics became faster in AFTER, but only in the patients with slow (V) over dotO(2) kinetics in BEFORE; the transient overshoot in fractional O-2 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 (V) over dotO(2) kinetics can effectively detect the functional improvements obtained by training.