High-Intensity Aerobic Exercise Improves Both Hepatic Fat Content and Stiffness in Sedentary Obese Men with Nonalcoholic Fatty Liver Disease

Abstract

We compared the effects of 12-week programs of resistance training (RT), high-intensity interval aerobic training (HIAT), and moderate-intensity continuous aerobic training (MICT). The primary goal was to evaluate the therapeutic effects of the exercise modalities for the management of nonalcoholic fatty liver disease (NAFLD). A total of 61 sedentary obese men with NAFLD were randomized into one of the following exercise regimens (RT, HIAT, or MICT). Hepatic fat content was decreased to a similar extent in the RT, HIAT, and MICT groups (-14.3% vs. -13.7% vs. -14.3%) without significant changes in weight and visceral fat. The gene expression levels of fatty acid synthesis were significantly decreased in the subjects' monocytes. Hepatic stiffness was decreased only in the HIAT group (-16.8%). The stiffness change was associated with restored Kupffer cell phagocytic function (+17.8%) and decreased levels of inflammation such as leptin (-13.2%) and ferritin (-14.1%). RT, HIAT, and MICT were equally effective in reducing hepatic fat content, but only HIAT was effective in improving hepatic stiffness and restoring Kupffer cell function. These benefits appeared to be independent of detectable weight and visceral fat reductions; the benefits were acquired through the modulation of in vivo fatty acid metabolism and obesity-related inflammatory conditions.

Figure 1. Flowchart showing the study process.

RT, resistance training; HIAT, high intensity aerobic training; MICT, moderate intensity continuous training.

Figure 2

Changes in the levels of adipokine (A), hepatokine and myokine (B) from the baseline to the end point of 12 weeks in a total of 52 subjects (RT = 19, HIAT = 20 and MICT = 13) with NAFLD who were randomly allocated to a 12-week training program. Analysis of SEPP used ANCOVA adjusted for baseline values to compare changed values between groups. ^†P < 0.05, significant difference between the baseline and the 12^th week. IL-6, interleukin 6; TNF-α, tumor necrosis factor alpha; SEPP1, selenoprotein P; FGF-21, fibroblast growth factor 21; MSTN, myostatin.

Figure 3

Changes in the levels of hepatic steatosis (A) and markers associated with liver fibrosis (B) from the baseline to the end point of 12 weeks in a total of 52 subjects (RT = 19, HIAT = 20 and MICT = 13) with NAFLD who were randomly allocated to a 12-week training program. ^†P < 0.05, significant difference between baseline and 12^th week; brackets *P < 0.05, significant difference among the three program groups. NAFLD-FS, non-alcoholic fatty liver disease fibrosis score; WFA⁺ -M2BP, wisteria floribunda agglutinin-positive human Mac-2-binding protein.