Effect of exercise training on insulin sensitivity, hyperinsulinemia and ectopic fat in black South African women: a randomized controlled trial. Issue 1 (1st July 2020)

• Record Type: Journal Article
• Authors: Fortuin-de Smidt, Melony C; Mendham, Amy E; Hauksson, Jon; Hakim, Olah; Stefanovski, Darko; Clamp, Louise; Phiri, Lindokuhle; Swart, Jeroen; Goff, Louise M; Micklesfield, Lisa K; Kahn, Steven E; Olsson, Tommy; Goedecke, Julia H
• Is Part Of: European journal of endocrinology. Volume 183:Issue 1(2020)
• Page Start: 51
• Page End: 61
• Publication Date: 2020-07-01
• Subjects: Endocrinology -- Periodicals; 616.4005
• DOI: 10.1530/EJE-19-0957
• Languages: English
• ISSNs: 0804-4643

Abstract

Abstract: Objective: We investigated the effects of a 12-week exercise intervention on insulin sensitivity (SI ) and hyperinsulinemia and associated changes in regional and ectopic fat. Research design and methods: Healthy, black South African women with obesity (mean age 23 ± 3.5 years) and of isiXhosa ancestry were randomised into a 12-week aerobic and resistance exercise training group ( n = 23) and a no exercise group (control, n = 22). Pre and post-intervention testing included assessment of SI, insulin response to glucose (AIRg), insulin secretion rate (ISR), hepatic insulin extraction (FEL ) and disposition index (DI) (AIRg × SI ) (frequently sampled i.v. glucose tolerance test); fat mass and regional adiposity (dual-energy X-ray absorptiometry); hepatic, pancreatic and skeletal muscle fat content and abdominal s.c. and visceral adipose tissue volumes (MRI). Results: Exercise training increased VO2peak (mean ± s.d. : 24.9 ± 2.42 to 27.6 ± 3.39 mL/kg/min, P < 0.001), SI (2.0 (1.2–2.8) to 2.2 (1.5–3.7) (mU/l) −1 min −1, P = 0.005) and DI (median (interquartile range): 6.1 (3.6–7.1) to 6.5 (5.6–9.2) × 10 3 arbitrary units, P = 0.028), and decreased gynoid fat mass (18.5 ± 1.7 to 18.2 ± 1.6%, P < 0.001) and body weight (84.1 ± 8.7 to 83.3 ± .9.7 kg, P = 0.038). None of these changes were observed in the control group, but body weight increased ( P = 0.030). AIRg, ISR and FEL, VAT, SAT and ectopic fat were unaltered after exercise training. The increase in SI and DI were not associated with changes in regional or ectopic fat. Conclusion: Exercise training increased SI independent from changes in hyperinsulinemia and ectopic fat, suggesting that ectopic fat might not be a principal determinant of insulin resistance in this cohort.