The decline in glucose homeostasis with aging may be due to the physical deconditioning and obesity that 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 nondiabetic sedentary older men. There were 14 men in a weekly behavioral modification/WL program, 10 in a 3 times/wk AEX program, 14 in an AEX+WL program, and 9 in the control (Con) group. The 10-mo intervention increased maximal oxygen consumption (VO2max) in both the AEX and AEX+WL groups [0.33 +/- 0.05 and 0.37 +/- 0.09 (SE) l/min, respectively], but VO2max did not significantly change in the WL (0.01 +/- 0.06 l/min) and Con groups (-0.04 +/- 0.05 l/min; P > 0.05). The AEX+WL and WL groups had comparable reductions in body weight (-8.5 +/- 0.9 and -8.8 +/- 1.2 kg, respectively) and percent fat (-5.5 +/- 0.7 and -5.9 +/- 1.1%, respectively) that were significantly greater than those 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 that in the other three 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.m-2.min-1) euglycemic clamps in the AEX and AEX+WL groups [1.66 +/- 0.50 and 1.76 +/- 0.41 mg.kg fat-free mass (FFM)-1.min-1, respectively] that were significantly greater than those in the WL (0.13 +/- 0.31 mg.kg FFM-1.min-1) and Con groups (-0.05 +/- 0.51 mg.kg FFM-1.min-1; n = 5). 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.
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http://dx.doi.org/10.1152/jappl.1996.81.1.318 | DOI Listing |
Endocr Res
December 2024
Baltimore VA Medical Center Geriatric Research, Education and Clinical Center (GRECC), VA Maryland Health Care System, Baltimore, MD, USA.
Purpose: The goal of this study was to explore the complex relationship between obesity, dietary content, weight loss, and cortisol concentrations in postmenopausal women with overweight and obesity.
Methods: Women completed basal cortisol testing, a dexamethasone suppression test (DST), DXA scan, 3-hour oral glucose tolerance test (OGTT), and food records before ( = 60) and a subset after 6-months of weight loss (WL; = 15) or aerobic exercise training+weight loss (AEX+WL, = 34).
Results: At baseline, plasma cortisol concentrations decreased significantly after DST in the entire group, a 54% suppression which was associated with basal glucose.
J Endocr Soc
August 2022
Department of Medicine, Division of Geriatric and Palliative Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Context: Adiponectin is an adipokine mainly secreted by adipocytes that regulates the metabolism of lipids and glucose. Liver receptor homolog-1 (LRH-1), also named NR5A2, is a nuclear receptor that regulates lipid metabolism and homeostasis.
Objective: The purpose of this study was to compare adiponectin and LRH-1 messenger RNA (mRNA) expression in adipose tissue and LRH-1 expression in skeletal muscle between men and women at baseline and to study the effects of aerobic exercise (AEX) training or weight loss (WL) on their expression.
Cells
December 2021
Baltimore VA Medical Center Geriatric Research, Education and Clinical Center, 10 N Greene Street, Baltimore, MD 21201, USA.
Aging and obesity contribute to insulin resistance with skeletal muscle being critically important for maintaining whole-body glucose homeostasis. Both exercise and weight loss are lifestyle interventions that can affect glucose metabolism. The purpose of this study was to examine the effects of a six-month trial of aerobic exercise training or weight loss on signaling pathways in skeletal muscle in the basal condition and during hyperinsulinemia during a glucose clamp in middle-aged and older adults.
View Article and Find Full Text PDFNutrients
August 2021
Division of Gerontology and Palliative Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
The purpose of this study was to compare changes in bone mineral density (BMD) over a 6 month follow up (period of weight regain) in overweight, postmenopausal women having previously completed a 6 month weight loss (WL) intervention with and without aerobic exercise (AEX). Women (BMI > 25 kg/m) underwent VOmax and DEXA scans at baseline, after 6 months of WL or AEX + WL, and at 12 months ad libitum follow up. Both groups lost ~9% body weight from 0 to 6 months and regained ~2% from 6 to 12 months, while losing ~4% of appendicular lean mass (ALM) across the 12-month study duration.
View Article and Find Full Text PDFJ Appl Physiol (1985)
July 2021
Department of Kinesiology, University of Maryland School of Public Health, College Park, Maryland.
Low skeletal muscle capillarization is associated with impaired glucose tolerance (IGT); however, aerobic exercise training with weight loss (AEX + WL) increases skeletal muscle capillarization and improves glucose tolerance in adults with IGT. Given that the expression of angiogenic growth factors mediates skeletal muscle capillarization, we sought to determine whether angiogenic growth factor levels are associated with low capillarization in those with IGT versus normal glucose tolerance (NGT) or to the benefits of AEX + WL in both groups. Sixteen overweight or obese men 50-75 yr of age completed 6 mo of AEX + WL with oral glucose tolerance tests and vastus lateralis muscle biopsies for measurement of muscle vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble fms-like tyrosine kinase receptor-1 (sFlt-1), and basic fibroblast growth factor (bFGF).
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