Exercise capacity and quadriceps muscle metabolism following training in subjects with COPD.
The aim of the study was to determine whether 16 sessions of exercise training, completed twice weekly, alters exercise capacity, quadriceps muscle metabolism, cross-sectional area (CSA) and strength in subjects with chronic obstructive pulmonary disease (COPD). We studied (a) 10 COPD subjects (mean age+/-sem = 71+/-2 years; FEV1 = 0.99+/-0.1 L) before and after 16 sessions of exercise training, and (b) 10 healthy subjects (age = 68+/-3 years). The COPD subjects underwent an incremental peak exercise test using a cycle ergometer and a 6-min walk test: both improved following exercise training (P < 0.05). Magnetic resonance spectroscopy measurements, in quadriceps muscle, of post-exercise phosphocreatinine (PCr) recovery kinetics were used to assess mitochondrial function in vivo: in the COPD subjects pre-training this was 19+/-8% lower than in healthy subjects (P = 0.03), but a 38+/-12% increase was seen in the COPD subjects following training (P = 0.003). Magnetic resonance imaging was used to assess quadriceps CSA: after training in the COPD subjects this showed a 7+/-2% increase (P = 0.03). Quadriceps strength, measured by the best of five maximum voluntary contractions, also showed a 32+/-11% increase in the COPD subjects (P = 0.007). Sixteen sessions of exercise training, performed twice weekly, increased exercise capacity as well as quadriceps mitochondrial capacity, CSA and strength in the subjects with COPD.
McKeough
Zoe J
ZJ
Department of Respiratory Medicine, Level 11 West, Building 75, Royal Prince Alfred Hospital, Missenden Rd, Camperdown, NSW, Australia 2050. z.mckeough@fhs.usyd.edu.au
Alison
Jennifer A
JA
Bye
Peter T P
PT
Trenell
Michael I
MI
Sachinwalla
Toos
T
Thompson
Campbell H
CH
Kemp
Graham J
GJ
D000368:Aged; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000378:metabolism*; D012129:Respiratory Function Tests