AUTHOR=Amador Manuel , Meza Cesar A. , McAinch Andrew J. , King George A. , Covington Jeffrey D. , Bajpeyi Sudip 

TITLE=Exercise-Induced Improvements in Insulin Sensitivity Are Not Attenuated by a Family History of Type 2 Diabetes

JOURNAL=Frontiers in Endocrinology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2020.00120

DOI=10.3389/fendo.2020.00120

ISSN=1664-2392

ABSTRACT=<p><bold>Introduction:</bold> A family history of type 2 diabetes (FH+) is a major risk factor for the development of insulin resistance and type 2 diabetes. However, it remains unknown whether exercise-induced improvements in insulin sensitivity and metabolic flexibility are impacted by a FH+. Therefore, we investigated whether improvements in insulin sensitivity, metabolic flexibility, body composition, aerobic fitness and muscle strength are limited by a FH+ following eight weeks of combined exercise training compared to individuals without a family history of type 2 diabetes (FH–).</p><p><bold>Methods:</bold> Twenty (<italic>n</italic> = 10 FH–, <italic>n</italic> = 10 FH+) young, healthy, sedentary, normoglycemic, Mexican-American males (age: FH– 22.50 ± 0.81, FH+ 23.41 ± 0.86 years; BMI: FH– 27.91 ± 1.55, FH+ 26.64 ± 1.02 kg/m<sup>2</sup>) underwent eight weeks of combined aerobic and resistance exercise training three times/week (35 min aerobic followed by six full-body resistance exercises). Insulin sensitivity was assessed via hyperinsulinemic euglycemic clamps. Metabolic flexibility was assessed by the change in respiratory quotient from fasted to insulin-stimulated states. Body composition was determined using dual-energy x-ray absorptiometry. Aerobic fitness was determined by a graded exercise test, and upper- and lower-body strength were assessed via one-repetition maximum bench press and leg strength dynamometer, respectively.</p><p><bold>Results:</bold> Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not different between groups (<italic>p</italic> &gt; 0.05). Eight weeks of combined aerobic and resistance exercise training improved insulin sensitivity (FH– <italic>p</italic> = 0.02, FH+ <italic>p</italic> = 0.002), increased fat free mass (FH– <italic>p</italic> = 0.006, FH+ <italic>p</italic> = 0.001), aerobic fitness (FH– <italic>p</italic> = 0.03, FH+ <italic>p</italic> = 0.002), and upper- (FH– <italic>p</italic> = 0.0001, FH+ <italic>p</italic> = 0.0001) and lower-body strength (FH– <italic>p</italic> = 0.0009, FH+ <italic>p</italic> = 0.0003), but did not change metabolic flexibility (<italic>p</italic> &gt; 0.05) in both groups. Exercise-induced improvements in metabolic outcomes were similar between groups.</p><p><bold>Conclusions:</bold> Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not compromised by a FH+. Additionally, a FH+ is not a limiting factor for exercise-induced improvements in insulin sensitivity, aerobic fitness, body composition, and strength in normoglycemic young Mexican-American men.</p>