TY - JOUR
T1 - Impact of aerobic exercise training on age-related changes in insulin sensitivity and muscle oxidative capacity
AU - Short, Kevin R.
AU - Vittone, Janet L.
AU - Bigelow, Maureen L.
AU - Proctor, David N.
AU - Rizza, Robert A.
AU - Coenen-Schimke, Jill M.
AU - Nair, K. Sreekumaran
PY - 2003/8/1
Y1 - 2003/8/1
N2 - Insulin resistance increases and muscle oxidative capacity decreases during aging, but lifestyle changes especially physical activity - may reverse these trends. Here we report the effect of a 16-week aerobic exercise program (n = 65) or control activity (n = 37) performed by men and women aged 21-87 years on insulin sensitivity and muscle mitochondria. Insulin sensitivity, measured by intravenous glucose tolerance test, decreased with age (r = -0.32) and was related to abdominal fat content (r = -0.65). Exercise increased peak oxygen uptake (VO2peak; 10%), activity of muscle mitochondrial enzymes (citrate synthase and cytochrome c oxidase, 45-76%) and mRNA levels of mitochondrial genes (COX4, ND4, both 66%) and genes involved in mitochondrial biogenesis (PGC-1α, 55%; NRF-1, 15%; TFAM, 85%). Exercise also increased muscle GLUT4 mRNA and protein (30-52%) and reduced abdominal fat (5%) and plasma triglycerides (25%). None of these changes were affected by age. In contrast, insulin sensitivity improved in younger people but not in middle-aged or older groups. Thus, the muscle mitochondrial response to 4 months of aerobic exercise training was similar in all age-groups, although the older people did not have an improvement in insulin sensitivity.
AB - Insulin resistance increases and muscle oxidative capacity decreases during aging, but lifestyle changes especially physical activity - may reverse these trends. Here we report the effect of a 16-week aerobic exercise program (n = 65) or control activity (n = 37) performed by men and women aged 21-87 years on insulin sensitivity and muscle mitochondria. Insulin sensitivity, measured by intravenous glucose tolerance test, decreased with age (r = -0.32) and was related to abdominal fat content (r = -0.65). Exercise increased peak oxygen uptake (VO2peak; 10%), activity of muscle mitochondrial enzymes (citrate synthase and cytochrome c oxidase, 45-76%) and mRNA levels of mitochondrial genes (COX4, ND4, both 66%) and genes involved in mitochondrial biogenesis (PGC-1α, 55%; NRF-1, 15%; TFAM, 85%). Exercise also increased muscle GLUT4 mRNA and protein (30-52%) and reduced abdominal fat (5%) and plasma triglycerides (25%). None of these changes were affected by age. In contrast, insulin sensitivity improved in younger people but not in middle-aged or older groups. Thus, the muscle mitochondrial response to 4 months of aerobic exercise training was similar in all age-groups, although the older people did not have an improvement in insulin sensitivity.
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U2 - 10.2337/diabetes.52.8.1888
DO - 10.2337/diabetes.52.8.1888
M3 - Article
C2 - 12882902
AN - SCOPUS:0042266366
SN - 0012-1797
VL - 52
SP - 1888
EP - 1896
JO - Diabetes
JF - Diabetes
IS - 8
ER -