Lipid Adaptations in Muscle and Liver Induced by Exercise in Type 2 Diabetes: A Systematic Review
Tauda Tauda Mauricio Ernesto, Jadue Arriaza Soraya Iffat, Cruzat Bravo Eduardo Joel, Bustos Barahona Rocío Beatriz, Reyes Sánchez Yoselyn Yudith.
Type 2 diabetes (T2D) is characterized by insulin resistance and ectopic lipid accumulation in muscle and liver. This dysfunction contributes to metabolic impairment and increased cardiovascular risk. Physical exercise is considered a cornerstone therapy, although the specific effects of different exercise modalities on these lipid depots are not fully defined.
Objective: To evaluate the impact of exercise on intramyocellular lipids (IMCL) and intrahepatic lipids (IHL) in adults with T2D and to identify the most effective protocols.
Methods: A systematic review was conducted following PRISMA 2020 guidelines in PubMed, Scopus, Web of Science, and Cochrane (2000–2023). Randomized and quasi-experimental trials analyzing aerobic, HIIT, resistance, or combined training and assessing IMCL/ IHL via MRI, ¹H-MRS, or biopsy were included. Risk of bias was evaluated with RoB 2/ROBINS-I, and certainty of evidence was rated using GRADE.
Results: Twelve studies (≈296 participants, 49–59 years) were included. Aerobic exercise and HIIT reduced IHL by 30–45 %, even without weight loss. Combined training produced similar reductions and additional improvements in strength and muscle profile. Changes in IMCL reflected a favorable reorganization toward an “athlete-like phenotype,” characterized by small, intramyofibrillar lipid droplets coupled to mitochondria (↑ PLIN5), associated with greater metabolic flexibility.
