Distinct effects of aerobic exercise training and weight loss on
glucose homeostasis in obese sedentary men.
Dengel, Donald R., Richard E. Pratley, James M. Hagberg, Ellen M.
Rogus, and Andrew P. Goldberg.
Department of Medicine, Division of Gerontology, University of
Maryland School of Medicine and Geriatric Service and Geriatric
Research, Education, and Clinical Center, Baltimore VA Medical
Center, Baltimore, Maryland, 21201; and Center on Aging, University
of Maryland, College Park, Maryland, 20742
APStracts 3:0125A, 1996.
The decline in glucose homeostasis with aging may be due to the
physical deconditioning and obesity which often develop with aging.
The independent and combined effects of aerobic exercise training
(AEX) and weight loss (WL) on glucose metabolism were studied in 47
non-diabetic, sedentary, older men. There were 14 men in a weekly
behavioral modification/WL program, 10 in a 3x/wk AEX program, 14 in
AEX+WL, and 9 in the control (CON) group. The 10-month intervention
increased maximal oxygen uptake (VO2max) in both the AEX and AEX+WL
groups (0.33+/-0.05, 0.37+/-0.09 L.min-1, respectively, mean+/-SEM),
but did not significantly (P<0.05) change in the WL (0.01+/-0.06
L.min-1), and CON (-0.04+/-0.05 L.min-1) groups. The AEX+WL and WL
groups had comparable reductions in weight (-8.5+/-0.9 and -8.8+/-1.2
kg,) and %fat (-5.5+/-0.7 and -5.9+/-1.1%) that were significantly
greater than in the CON and AEX groups. Oral glucose tolerance tests
showed significant reductions in insulin responses in the AEX, WL,
and AEX+WL groups, but the decrease in insulin response in the AEX+WL
group was significantly greater than in the other 3 groups. The
glucose area decreased significantly in the WL and AEX+WL groups, but
did not change in the CON or AEX groups. There were significant
increases in insulin-mediated glucose disposal rates as measured by
the hyperinsulinemic (600 pmol/m2.min) euglycemic clamps in the AEX
and AEX+WL groups (1.66+/-0.50 and 1.76+/-0.41 mg/kgFFM.min,
respectively) which were significantly greater than in the WL
(0.13+/-0.31 mg/kgFFM.min) and CON (-0.05+/-0.51 mg/kgFFM.min, n=5)
groups. These data suggest that AEX and WL improve glucose metabolism
through different mechanisms and that the combined intervention of
AEX+WL is necessary to improve both glucose tolerance and insulin
sensitivity in older men.
Received 22 November 1995; accepted in final form 19 February
1996.
APS Manuscript Number A1220-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 March 96