Key result
An 8-week endurance training program further decreased muscle oxygen saturation during constant work rate cycling exercise in both healthy subjects and COPD patients (P<0.05).
Why the study?
It was hypothesized that training-induced changes in muscle oxygen saturation assessed by near-infrared spectroscopy during cycling exercise could serve as a useful marker of quadriceps training effects in COPD patients.
Does 8-week endurance training alter muscle oxygen saturation assessed by NIRS during exercise in healthy subjects and COPD patients?
Does 8-week endurance training alter muscle oxygen saturation assessed by NIRS during exercise in healthy subjects and COPD patients?
p-value: p=<0.05
Endurance training decreases muscle oxygen saturation during exercise and increases rebound after unloading, suggesting enhanced muscle oxygen transfer and utilization in both healthy subjects and COPD patients.
StO2 changes may track training effects in COPD; hypothesis-generating and requires validation before clinical use.
Summary Aim We hypothesize that training‐induced changes in muscle oxygen saturation (StO2) assessed by near‐infrared spectroscopy (NIRS) during constant work rate cycling exercise (CWRE) may be a useful marker of the effects of training at ‘vastus medialis’ of the quadriceps in patients with chronic obstructive pulmonary disease (COPD). Methods Incremental exercise [peak oxygen uptake (VO2)] and CWRE at 70% pretraining peak VO2, before and after 8‐w training, were done in 10 healthy age‐matched subjects (H) [80% men, 65(11) years, FEV1 105(14)%] and 16 COPD patients [94% men, 70(5) years, FEV1 46(11) %] encompassing the entire spectrum of disease severity, recruited in the outpatient clinics. NIRS was used to assess StO2 in the ‘vastus medialis’ of the left quadriceps. Results Pretraining CWRE decreased StO2 (P<0·05) and generated marked StO2 rebound (P<0·001) after unloading in the two groups. After training, VO2 peak increased in H [253(204) ml min−1] (P<0·01) and in COPD [180(183) ml·min−1] (P = 0·01) and blood lactate fell [−4·4 (2·7) and −1·6(2·3) mmol·m−1] (P<0·05 each). Training generated a further fall in StO2 during CWRE [−10(12)% and −10(10)%, P<0·05] and increased StO2 rebound after unloading [8(7)% and 5(9)%, P<0·05] in both groups. Conclusion Endurance training further decreased StO2 during CWRE, similarly in both groups, likely due to training‐induced enhancement of muscle O2 transfer and utilization. Training‐induced StO2 fall during CWRE may be useful individual marker for non‐invasive assessment of enhanced muscle aerobic post‐training function.
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Barberán-García et al. (2019) studied Chronic obstructive pulmonary disease (COPD) (n=26). Endurance training vs. Pre-training baseline was evaluated on Change in muscle oxygen saturation (StO2) during constant work rate cycling exercise (CWRE) (p=<0.05). An 8-week endurance training program further decreased muscle oxygen saturation during constant work rate cycling exercise in both healthy subjects and COPD patients (P<0.05).
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