The effect of blood-flow restricted strength and sprint training on skeletal muscle mitochondrial function in persons with CCPD: a randomised controlled study

Introduction: Blood-flow restricted training (BFRT) was recently introduced to pulmonary rehabilitation. It remains unknown whether it has the potential to ameliorate the skeletal muscle mitochondrial dysfunction associated with COPD.

Aim: We aimed to investigate the effects of BFRT (as low-load strength and sprint training) vs high-load strength training and sprint training (HL) on mitochondrial function in persons with stable COPD.

Methods: We randomly assigned participants to 6 weeks lower limb BFRT (strength: 70% occlusion pressure, 30% 1-repetition maximum; sprint: 30s all-out sprints, 70% occlusion pressure during breaks) or HL (strength: 70% 1-repetition maximum; sprint: 30s all-out sprints). Primary outcome was mitochondrial respiratory capacity and H2O2 emission (Oroboros O2k) in permeabilised muscle fibres sampled from vastus lateralis biopsies before and after the intervention. We secondarily investigated maximal voluntary strength.

Results: The study is ongoing. To date, 11 participants (69 [67, 72] years, FEV1 61 [49, 70] % pred.) completed the study, 3 dropped out. Mitochondrial complex I + II state 3 respiration changed by -0.20 (−1.08, 1.40) pmol O2/s/mg ww in the BFRT group and by 2.72 (2.27, 3.78) in the HL group. Maximal mitochondrial H2O2 emission changed by -0.08 (−1.62, 0.40) pmol H2O2/s/mg ww in the BFRT group and by 0.25 (−1.43, 0.61) in the HL group. Both groups increased maximal voluntary strength without clinically relevant between-group differences.

Conclusions: Six weeks of BFRT may reduce overactivity of mitochondrial complex I + II-linked respiration and maximal H2O2 emission in comparison to HL.