Eight Weeks of Combined Exercise Training Induced Improvements in Insulin Sensitivity is Associated with Improvement in Aerobic Capacity, but not with Improvement in Strength.

Authors

Manuel Amador, University of Texas at El PasoFollow
Cesar A. Meza, University of Texas at El PasoFollow
Cynthia K. Montenegro, University of Texas at El PasoFollow
Jeffrey D. Covington, Louisiana State UniversityFollow
Andrew McAinch, Victoria University, St. AlbansFollow
George King, University of Texas at El PasoFollow
Sudip Bajpeyi, University of Texas at El PasoFollow

Abstract

A lifestyle compromised of predominantly sedentary behavior is a risk factor that promotes the development of metabolic syndrome. It has been demonstrated that individuals with blunted insulin sensitivity (IS) and metabolic flexibility (MF) tend to be more prone to develop the disease. An increase in physical activity is recommended in order to prevent cardiovascular disease and type 2 diabetes mellitus. PURPOSE: to determine whether healthy, sedentary, normoglycemic, Mexican American men without a family history of type 2 diabetes are able to improve IS and MF after participating in a combined (aerobic/resistance) exercise intervention. METHODS: Subjects (n=6; 21.83±0.8 years; BMI 28.92 ± 1.6 kg/m²), participated in 8 weeks of combined exercise training three times per week (35 minutes of aerobic training & 45 minutes of resistance training/session). Upper body 1 repetition maximum (1RM) was measured using the flat barbell bench press and lower body 1RM was measured using a back leg strength dynamometer. IS was assessed using the hyperinsulinemic euglycemic clamp (clamp). Insulin dose administered to each subject was set 80mU/m²/min. MF was assessed by determining change in RQ (ΔRQ) at the steady state of the clamp compared to RQ measured at baseline/resting. Participants were provided with standard diet 5 days before pre and post intervention testing in order to control for the effects of diet on insulin sensitivity. Body composition was measured using dual x-ray absorptiometry. RESULTS: IS improved significantly after the 8 weeks of combined exercise training (3.18±0.35 to 3.75±0.34 mg/kg EMBS/min, p=0.05). There was no significant improvement in MF (0.06±0.02 to 0.08±0.02 ∆RER, p=0.19). Body weight significantly increased (3.76%; 81.06±5.38 to 84.11±5.67 kg, p=0.01) with no change in fat mass and a trend to increase in fat free mas (2.8%; 55.92±2.77 to 57.5±2.38 kg, p=0.1). Upper body strength significantly increased (168.3±26.57 to 195±26.04 lb., p=0.001). Lower body strength increased (356.7±46.52 to 428.3±34.51 lb., p=0.02).VO₂ max improved significantly (3.90±0.14 to 4.19±0.16 L/min, p=0.037). Improvement in IS was associated with an increase in VO₂max (r=0.92, p=0.008) but not with the improvement in strength. Improvement in MF was significantly correlated with fasting glucose (r=-0.83, p=0.04), and an increase in lean mass (r=0.82, p=0.04). CONCLUSION: 8 weeks of combined exercise improves insulin sensitivity in healthy, sedentary, normoglycemic Hispanic men. Improvement in insulin sensitivity is associated with improvement in aerobic fitness but not gain in upper and lower body strength.

Recommended Citation

Amador, Manuel; Meza, Cesar A.; Montenegro, Cynthia K.; Covington, Jeffrey D.; McAinch, Andrew; King, George; and Bajpeyi, Sudip (2017) "Eight Weeks of Combined Exercise Training Induced Improvements in Insulin Sensitivity is Associated with Improvement in Aerobic Capacity, but not with Improvement in Strength.," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 9, Article 48.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss9/48