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 3:0212A, 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 VO2max 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 body 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 1 May 96