The Effect of a Novel Low-Volume Aerobic Exercise Intervention on Liver Fat in Type 2 Diabetes: A Randomized Controlled Trial
Angelo Sabag, Kimberley L. Way, Rachelle N. Sultana, Shelley E. Keating, James Gerofi, Vivienne Chuter, Nuala M. Byrne, Michael K. Baker, Jacob George, Ian D. Caterson, Stephen M. Twigg, Nathan A. Johnson
Abstract
OBJECTIVE The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), or placebo (PLA) intervention on liver fat, glycemia, and cardiorespiratory fitness using a randomized placebo-controlled design. RESEARCH DESIGN AND METHODS Thirty-five inactive adults (age 54.6 ± 1.4 years, 54% male; BMI 35.9 ± 0.9 kg/m2) with obesity and type 2 diabetes were randomized to 12 weeks of supervised MICT (n = 12) at 60% VO2peak for 45 min, 3 days/week; HIIT (n = 12) at 90% VO2peak for 4 min, 3 days/week; or PLA (n = 11). Liver fat percentage was quantified through proton MRS. RESULTS Liver fat reduced in MICT (−0.9 ± 0.7%) and HIIT (−1.7 ± 1.1%) but increased in PLA (1.2 ± 0.5%) (P = 0.046). HbA1c improved in MICT (−0.3 ± 0.3%) and HIIT (−0.3 ± 0.3%) but not in PLA (0.5 ± 0.2%) (P = 0.014). Cardiorespiratory fitness improved in MICT (2.3 ± 1.2 mL/kg/min) and HIIT (1.1 ± 0.5 mL/kg/min) but not in PLA (−1.5 ± 0.9 mL/kg/min) (P = 0.006). CONCLUSIONS MICT or a low-volume HIIT approach involving 12 min of weekly high-intensity aerobic exercise may improve liver fat, glycemia, and cardiorespiratory fitness in people with type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycemia.