Muscle metabolites at rest and exercise
| COPD patients (n = 18) | Healthy controls (n = 8) | |||
|---|---|---|---|---|
| Rest | Exercise induced change (95% CI) | Rest | Exercise induced change (95% CI) | |
| PCr, phosphocreatine; ATP, adenosine triphosphate; ADP, adenosine diphosphate; AMP, adenosine monophosphate; IMP, inosine monophosphate; TAN pool, total adenine nucleotide pool. | ||||
| Resting figures are mean (SD) values. Mean (95% confidence interval) changes are shown. Negative values denote a decrease after exercise. | ||||
| All units are mmol/kg dry wt. Symbols of statistical significance for resting values refer to comparisons between COPD and control groups using the unpaired Student’s t test. Symbols of statistical significance for the response to exercise refer to within subject comparison of metabolite changes using the paired Student’s t test. There were no statistically significant differences in the exercise induced changes in metabolites between the COPD and control groups. | ||||
| *p<0.01; †p<0.05; ‡p = 0.053; §p = 0.063. | ||||
| PCr | 67.9 (17.1) | −38.1 (−48.3 to −27.9)* | 55.4 (12.7) | −30.6 (−45.5 to −15.8)* |
| Lactate | 2.3 (1.5) | 25.7 (12.4 to 39.0)* | 7.5 (4.7)* | 42.1 (26.8 to 57.4)* |
| ATP | 19.5 (4.5) | −4.3 (−7.0 to −1.6)* | 24.1 (4.9)† | −4.8 (−9.7 to 0.08)‡ |
| ADP | 2.67 (0.87) | 0.53 (−0.03 to 1.09) | 3.1 (1.2) | −0.03 (−0.84 to 0.79) |
| AMP | 0.03 (0.03) | 0.03 (−0.02 to 0.08) | 0.24 (0.17)* | −0.02 (−0.21 to 0.18) |
| TAN pool | 22.2 (5.2) | −3.7 (−6.8 to −0.7)† | 27.4 (6.0)† | −4.8 (−10 to 0.3)§ |
| IMP | 0.14 (0.06) | 2.03 (0.64 to 3.42)* | 0.28 (0.09)* | 1.6 (0.42 to 2.79)* |
| Inosine | 0.73 (1.05) | −0.26 (−0.75 to 0.24) | 2.06 (0.30)* | −0.17 (−0.58 to 0.24) |
| Xanthine | 0.07 (0.03) | −0.01 (−0.03 to 0.01) | 0.38 (0.08)* | −0.02 (−0.15 to 0.10) |