Dissociation between exercise-induced reduction in liver fat and changes in hepatic and peripheral glucose homoeostasis in obese patients with non-alcoholic fatty liver disease

Abstract

35Non-Alcoholic Fatty Liver Disease (NAFLD) is associated with multi-organ (hepatic, skeletal muscle, 36 adipose tissue) insulin resistance (IR). Exercise is an effective treatment for lowering liver fat but its 37 effect on insulin resistance in NAFLD is unknown. 38We aimed to determine whether supervised exercise in NAFLD would reduce liver fat and improve 51With exercise, peripheral insulin sensitivity significant increased (following high-dose insulin) despite 52 no significant change in hepatic glucose production (following low-dose insulin); no changes were 53 observed in the control group. 54Although supervised exercise effectively reduced liver fat, improving peripheral IR in NAFLD, the 55 reduction in liver fat was insufficient to improve hepatic IR.

Exercise Training as Treatment of Nonalcoholic Fatty Liver Disease

“…Frequency of exercise dosage ranged from three times per week for 30 min per day to seven times per week for 60 min per day [19][20][21]25,26]. Only three studies included more than 30 participants in at least one intervention group [21,22,28]. To date, all of the exercise intervention studies for NAFLD/NASH are limited by small sample size and insufficient samples size by which to assess improvement in hepatic fibrosis.…”

“…Maximum heart rate (MHR), heart rate reserve (HRR), maximal predicted heart rate (MPHR), metabolic equivalent of task (MET), or VO 2max were used to determine exercise intensity prescriptions-where intensities range from light to moderate (30-39% of HRR, 57-63% of HRR, 2.0-3.9 METs, and 37-45% of VO 2max ) moderate (40-59% of HRR, 64-76% of HRR, 4.0-5.9 METs, and 46-63% of VO 2max ), and vigorous (60-89% of HRR, 77-95% of HRR, 6.0-8.4 METs, and 64-90% of VO 2max ) [9][10][11][19][20][21][22]24,26,27,29]. Exercise modalities included recreational walking, treadmill running, cycle ergometry, cross-training, rowing, and rhythmic exercise [10,11,[20][21][22][23][24][25][26][27]. Six studies used single modality exercise, while four studies used a multitude of exercise modalities [9][10][11][20][21][22][23][25][26][27].…”

“…Exercise modalities included recreational walking, treadmill running, cycle ergometry, cross-training, rowing, and rhythmic exercise [10,11,[20][21][22][23][24][25][26][27]. Six studies used single modality exercise, while four studies used a multitude of exercise modalities [9][10][11][20][21][22][23][25][26][27]. Only two studies did not specify aerobic training.…”

“…Only two studies did not specify aerobic training. Exercise intervention lengths ranged from one week to one year, with the most commonly used duration as 16-weeks [9,[19][20][21][22][23]25,26,28]. Frequency of exercise dosage ranged from three times per week for 30 min per day to seven times per week for 60 min per day [19][20][21]25,26].…”

“…Nine randomized control trials and four uncontrolled studies have investigated the effects of aerobic training in NAFLD (Table 1) [9][10][11][19][20][21][22][23][24][25][26][27][28]. All of the studies included at least one aerobic training experimental group, with three studies containing multiple aerobic training groups of differing exercise intensities [11,22,24].…”