Neunhäuserer D;Hudelmaier M; Niederseer DVecchiato M; Wirth W; Steidle-Kloc E; Kaiser B; Lamprecht B;Ermolao A; Studnicka M;

Medicine and science in sports and exercise [Med Sci Sports Exerc] 2023 Aug 02.
Date of Electronic Publication: 2023 Aug 02.

Objective: Exercise training is a cornerstone of the treatment of COPD while the related inter-individual heterogeneity in skeletal muscle dysfunction and adaptations are not yet fully understood. We set out to investigate the effects of exercise training and supplemental oxygen on functional and structural peripheral muscle adaptation.
Methods: In this prospective, randomized, controlled, double-blind study, 28 patients with non-hypoxemic COPD (FEV1 45.92 ± 9.06%) performed six-weeks of combined endurance and strength training, three times a week while breathing either supplemental oxygen or medical air. The impact on exercise capacity, muscle strength and quadriceps femoris muscle cross-sectional area (CSA), was assessed by maximal cardiopulmonary exercise testing, ten-repetition maximum strength test of knee extension, and magnetic resonance imaging, respectively.
Results: After exercise training, patients demonstrated a significant increase of functional capacity, aerobic capacity, exercise tolerance, quadriceps muscle strength and bilateral CSA. Supplemental oxygen affected significantly the training impact on peak work rate when compared to medical air (+0.20 ± 0.03 vs +0.12 ± 0.03 Watt/kg, p = 0.047); a significant increase in CSA (+3.9 ± 1.3 cm2, p = 0.013) was only observed in the training group using oxygen. Supplemental oxygen and exercise induced peripheral desaturation were identified as significant opposing determinants of muscle gain during this exercise training intervention, which led to different adaptations of CSA between the respective subgroups.
Conclusions: The heterogenous functional and structural muscle adaptations seem determined by supplemental oxygen and exercise induced hypoxia. Indeed, supplemental oxygen may facilitate muscular training adaptations, particularly in limb muscle dysfunction, thereby contributing to the enhanced training responses on maximal aerobic and functional capacity.
Competing Interests: Conflict of Interest and Funding Source: The Salzburg COPD Exercise and Oxygen (SCOPE) study was supported by an unconditional and unrestricted grant by Air Liquide. All authors declare hereby to have no conflicts of interest. The results of this study are presented clearly, honestly and without fabrication, falsification, or inappropriate data manipulation. The results of the present study do not constitute endorsement by the American College of Sports Medicine.