CONTEXT: Intramuscular lipid content increases with aging and obesity and is directly related to impaired glucose tolerance and insulin resistance. OBJECTIVE: Our purpose was to determine the effects of aerobic exercise training (AEX) with and without weight loss (WL) on midthigh low-density muscle (LDM; a measure of im lipid) and whether changes in LDM impact glucose tolerance in sedentary older men. DESIGN: Forty-six men (60.4 +/- 1.1 yr) completed 6 months of AEX (n = 34) or AEX + WL (n = 12) and had oral glucose tolerance tests (OGTTs) and computed tomography measures of LDM and regional abdominal and thigh fat depot areas. RESULTS: At baseline, LDM area directly correlated with fasting plasma glucose (FPG), 120-min glucose (G(120)), and glucose area under the curve (G(AUC)) during an OGTT (r = 0.44, r = 0.51, and r = 0.54, respectively, P < 0.01). After the interventions, the AEX + WL group had greater decreases in LDM (-13.5 vs. +1.3%, respectively), FPG (-8.3 vs. +2.1%, respectively), G(120) (-22.5 vs. -3.6%, respectively), and G(AUC) (-17.3 vs. - 3.1%, respectively) than the AEX group. In the entire sample, the decreases in LDM correlated with reductions in FPG, G(120), and G(AUC) during an OGTT (r = 0.31, r = 0.34, and r = 0.41, P < 0.05). Changes in other regional fat depots did not independently correlate with glucose tolerance or insulin responses. CONCLUSION: AEX + WL is more efficacious than AEX for reducing LDM and glucose tolerance. The improvement in glucose tolerance may be partially mediated by decreases in LDM in older men.
CONTEXT: Intramuscular lipid content increases with aging and obesity and is directly related to impaired glucose tolerance and insulin resistance. OBJECTIVE: Our purpose was to determine the effects of aerobic exercise training (AEX) with and without weight loss (WL) on midthigh low-density muscle (LDM; a measure of im lipid) and whether changes in LDM impact glucose tolerance in sedentary older men. DESIGN: Forty-six men (60.4 +/- 1.1 yr) completed 6 months of AEX (n = 34) or AEX + WL (n = 12) and had oral glucose tolerance tests (OGTTs) and computed tomography measures of LDM and regional abdominal and thigh fat depot areas. RESULTS: At baseline, LDM area directly correlated with fasting plasma glucose (FPG), 120-min glucose (G(120)), and glucose area under the curve (G(AUC)) during an OGTT (r = 0.44, r = 0.51, and r = 0.54, respectively, P < 0.01). After the interventions, the AEX + WL group had greater decreases in LDM (-13.5 vs. +1.3%, respectively), FPG (-8.3 vs. +2.1%, respectively), G(120) (-22.5 vs. -3.6%, respectively), and G(AUC) (-17.3 vs. - 3.1%, respectively) than the AEX group. In the entire sample, the decreases in LDM correlated with reductions in FPG, G(120), and G(AUC) during an OGTT (r = 0.31, r = 0.34, and r = 0.41, P < 0.05). Changes in other regional fat depots did not independently correlate with glucose tolerance or insulin responses. CONCLUSION:AEX + WL is more efficacious than AEX for reducing LDM and glucose tolerance. The improvement in glucose tolerance may be partially mediated by decreases in LDM in older men.
Authors: Britta Larsen; John Bellettiere; Matthew Allison; Robyn L McClelland; Iva Miljkovic; Chantal A Vella; Pamela Ouyang; Kimberly R De-Guzman; Michael Criqui; Jonathan Unkart Journal: Metabolism Date: 2020-07-23 Impact factor: 8.694
Authors: Robert M Blew; Vinson R Lee; Jennifer W Bea; Megan C Hetherington-Rauth; Jean-Phillipe Galons; Maria I Altbach; Timothy G Lohman; Scott B Going Journal: J Clin Densitom Date: 2018-03-23 Impact factor: 2.617
Authors: Steven J Prior; Andrew P Goldberg; Heidi K Ortmeyer; Eva R Chin; Dapeng Chen; Jacob B Blumenthal; Alice S Ryan Journal: Diabetes Date: 2015-06-11 Impact factor: 9.461
Authors: Margaret A Crawford; Michael H Criqui; Nketi Forbang; Jonathan T Unkart; Matthew A Allison; Britta A Larsen Journal: Metabolism Date: 2020-04-13 Impact factor: 8.694