Table 2.

Randomized Controlled Studies Evaluating the Effect of Aerobic Exercise on MAFLD

Reference	Country	N	Intervention			Controls	Main Findings
			Intensity	Sessions/Week	Duration
Sullivan S, 2012131	USA	19 obese MAFLD patients	45–55 VO2 peak, 30–60 minutes	5	16	No exercise	● Exercise ↓ IHLC (10.3±4.6%) ● Exercise had no effect on weight or % of body fat
Hallsworth K, 201533	UK	23 MAFLD patients	H-I interval training	3	12 weeks	Standard of care	● Exercise associated with:  ● ↓ liver fat and whole body fat mass  ● ↓ ALT and AST  ● ↑ early diastolic filling rate ● No effect on glucose or lipid metabolism
Keating SE, 201558	Australia	48 inactive overweight/ obese adults	1. L/M-I (50% VO2 peak), 60 min, 4x/week 2. H-I (70% VO2 peak), 45 min, 3x/week 3. L/M-I (50% VO2 peak), 45 min, 3x/week		8 weeks	No exercise	● L/M-I, 60 min, 4x/week: ↓ IHLC 2.62±1.00%, ↓ VAT 386.8±119.5 cm2 ● H-I, 45 min, 3x/week: ↓ IHLC 2.38±0.73%, ↓ VAT 258.4±87.2 cm2 ● L/M-I, 45 min, 3x/week: ↓ IHLC 0.84±0.45%, ↓ VAT 212.9±105.5 cm2 ● Placebo: ↑ IHLC 1.10±0.62%, ↑ VAT 92.6±83.5 cm2
Zhang HS, 2016126	China	220 MAFLD patients with central obesity	1. H-I: 65–80% maximal HR 2. M-I: 45–55% maximal HR	150 minutes	6 months	No exercise	● No difference on IHLC in M-I vs H-I exercise, even though H-I exercise associated with higher decrease in body weight ● No effect on aminotransferases
Shojaee-Moradie F, 2016127	UK	27 sedentary MAFLD patients	1 hour at 40–60% HR reserve	4–5	16 weeks	Conventional life-style advice	● Exercise versus control ↓ IHLC, visceral fat and subcutaneous abdominal fat and ↑ VLDL clearance
Cuthbertson DS, 2016140	UK	69 MAFLD patients	30% HR reserve 30 minutes → 60% HR reserve 45 minutes	3 → 5	16 weeks	Counseling	● Greater ↓ of IHLC in intervention group (4.7% [0.01–9.4]), improvement on insulin sensitivity and SC abdominal fat
Rezende R, 2016132	Brazil	40 sedentary post-menopausal women	Treadmill aerobic exercise	120 minutes	24 weeks	No exercise	● Exercise associated with ↓ waist circumference ● Exercise did not associate with improvements on steatosis (by CAP-Fibroscan) or glucose metabolism
Cheng S, 2017139	China	115 patients with MAFLD and IR, 50–65 years	60–75% VO2 max, 30–60 minutes ± fiber-enriched diet	2–3	8.6 months	No intervention	● Effect on IHLC:  ● exercise alone: ↓ 24.4%  ● diet alone: ↓ 23.2%  ● exercise + diet: ↓ 47.9%  ● no intervention: ↓ 20.9% ● Only exercise associated with ↓ HbA1c
Winn NC, 2018133	USA	23 obese adults	H-I interval (4 min 80%VO2 peak/3 min, 50%VO2 peak) or M-I continuous (55%VO2 peak, 60 min). Duration calculated to spend 400 kcal		4 weeks	No exercise	● Both exercises similarly ↓ IHLC (H-I −37.0±12.4% and M-I 20.1±6.6%) ● Exercise ↓ postprandial insulin and lipid peroxidation levels ● Exercise did not ↓ BMI, visceral AT or liver enzymes
Abdelbasset WK, 2019135	Saudi Arabia	32 obese MAFLD patients	H-I interval training, 40 minutes	3	8 weeks	No exercise	● Exercise associated with:  ● ↓ IHLC (12.4±4.5% to 10.1±1.3%)  ● ↓ visceral AT (184.5±12.3 to 160.4±11.6 cm2)  ● ↓ BMI (36.3±4.5 to 34.1±3.1 kg/m2)  ● improvement in glucose and lipid metabolism
Abdelbasset WK, 2020136	Saudi Arabia	72 obese diabetic MAFLD patients	H-I interval vs M-I continuous	3	8 weeks	No exercise	● No differences between H-I interval or M-I continuous on IHLC, visceral AT, BMI or glucose metabolism
O’Gorman P, 2020157	Ireland	24 biopsy-proven MAFLD patients	Supervised and unsupervised sessions	3–5	12 weeks	Standard of care	● Exercise associated with ↓ hepatocyte ballooning and fibrosis for one stage, but showed no effect on steatosis, lobular inflammation or NAFLD activity score

Abbreviations: AT, adipose tissue; BMI, body mass index; H, high; HR, heart rate; IHLC, intra-hepatic liver content; IR, insulin resistance; L, low; M, moderate, VLDL, very-low density lipoproteins.