Impaired substrate oxidation in healthy elderly XXXX after eccentric exercise.

@entity1 @entity28 @entity1009 @entity908 @entity1735 @entity4854 @entity413
The metabolic response to eccentric exercise in healthy older adults is unknown. Therefore, substrate metabolism was examined in the basal state and after sustained @entity4854 (180 min, 10 mM) in eight healthy, sedentary older [66 +/- 2 yr; body mass index (BMI) of 25.5 +/- 1.2 kg/m] and nine younger (23 +/- 1 yr; BMI of 23.6 +/- 1.7 kg/m) @entity1 , under control conditions and 48 h after eccentric exercise. Indirect calorimetry was performed to evaluate @entity1735 and lipid oxidation (C(ox) and L(ox), respectively). Eccentric exercise caused muscle soreness and increased plasma @entity908 kinase in both groups of @entity1 (P < 0.02). Although a similar level of @entity4854 was maintained in the two groups, @entity413 infusion rates were lower (P < 0.001) in the older @entity1 . Compared with basal levels, @entity4854 stimulated an increase in C(ox) and a decrease in L(ox) during the control and exercise trials in the younger group (P < 0.03), but only during the control trial in the older subjects (P < 0.007). C(ox) was unchanged after eccentric exercise in the younger @entity1 [4.00 +/- 0.30 vs. 3.54 +/- 0.44 mg x kg fat-free mass (FFM)(-1) x @entity1009 ); exercise vs. control] but was suppressed by 20% in the older group (3.37 +/- 0.37 vs. 4.21 +/- 0.23 mg x kg FFM(-1) x @entity1009 ); P < 0.04). Moreover, L(ox) was reduced by 38% in the younger subjects (0.47 +/- 0.09 vs. 0.76 +/- 0.10 mg x kg FFM(-1) x @entity1009 ); P< 0.03) but was augmented by 89% in the older group (0.68 +/- 0.11 vs. 0.36 +/- 0.08 mg x kg FFM(-1) x @entity1009 ); P < 0.04). In addition, @entity4854 -stimulated C(ox), L(ox), and respiratory exchange ratio responses to eccentric exercise were related to abdominal adiposity (r = -0.57, P < 0.04, r = 0.68, P < 0.02 and r = -0.60, P < 0.02, respectively). Despite normal @entity413 tolerance and the absence of @entity28 per se, older @entity1 experience a reduction in @entity1735 oxidation in response to @entity4854 after eccentric exercise.
