Background: Physical activity (PA) reduces visceral adipose tissue (VAT) in adults; however, the dose to reduce VAT in youth is unclear. Objective: To examine whether high intensity PA preferentially reduces waist circumference (WC) and VAT compared to lower intensity PA. Design: Randomized controlled trial. Participants: Youth were 13-18yrs, overweight, with one additional risk factor for type 2 diabetes (T2DM). Intervention: 6-months, exercising 3 times/week at a high intensity (70-85% of Heart Rate Reserve HRR), or low intensity (40-55% HRR). Primary outcome: VAT (cm2) measured by MRI at L4-L5, and WC at the height of the iliac crest (cm). Results: 94 Youth were randomized to either high intensity (n=30); low intensity (n=32) or control (n=32). Changes in WC and VAT were not significant across groups. A trend towards a reduction in VAT in the training groups, compared to controls was demonstrated in sub-analysis (-14.3 ± 9.6 % vs. +0.01 ± 0.4 %, p= 0.059). Peak fitness increased significantly in both the high and low intensity arms (1.3 ± 0.6 and 1.4 ± 0.6 ml/kg/min, p < 0.05). Conclusions: Training at 55-65% HRR improves fitness by ~10%, and ~2 days/week elicits modest non-significant reductions in VAT in overweight youth.

This project investigated the effects of exercise and epinephrine on the mRNA expression of peroxisome proliferator activated receptor gamma coactivator-1 alpha (PGC-1 alpha), a master regulator of mitochondrial biogenesis, in rat adipose tissue. Rats that swam 2 hours daily for 4 weeks had increased mitochondrial marker proteins and PGC-1 alpha mRNA expression in epididymal and retroperitoneal adipose tissue (p<0.05). Adipose tissue organ culture treatment with epinephrine increased (p<0.05) PGC-1 alpha mRNA expression in both depots, but only epididymal adipose responded to a supra-physiological dose. Beta blockade attenuated the effects of an acute bout of exercise on PGC-1 alpha mRNA expression in epididymal, but not in retroperitoneal adipose tissue. This is the first study to demonstrate that rat white adipose tissue PGC-1 alpha mRNA expression is increased by acute and chronic exercise and epinephrine. Increases in circulating catecholamine levels might be one potential mechanism mediating exercise induced increases in PGC-1 alpha mRNA expression in rat abdominal adipose tissue. / Nutrition and Metabolism

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available online.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 9 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2007. / Includes bibliographical references (p. 139-160).

Thesis (Ph. D.)--Cornell University, 1918. / "Author's abstract of this paper issued by the Bibliographic service, January 12." "Reprinted from the Journal of morphology, vol. 30, no. 2, March, 1918." Cornell Univ. Libr. Bibliography: p. 510-513.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Jeanne H Freeland-Graves. Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Wisconsin--Madsion, 1977. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.