Exercise Training to Decrease Ectopic Intermuscular Adipose Tissue in Individuals With Chronic Diseases: A Systematic...

Area of Science:

• Exercise Physiology
• Skeletal Muscle Metabolism
• Chronic Disease Management

Background:

• Intermuscular adipose tissue (IMAT) accumulation in skeletal muscle is linked to muscle mass and strength loss, reduced physical performance, inflammation, and metabolic dysfunction in individuals with chronic conditions.
• Addressing IMAT is crucial for maintaining skeletal muscle homeostasis and overall health in adult populations facing chronic diseases.

Purpose of the Study:

• To systematically evaluate the impact of different exercise training modalities on intermuscular adipose tissue (IMAT) in adults with chronic diseases.
• To synthesize evidence from randomized controlled trials (RCTs) to determine the efficacy of aerobic, resistance, or combined exercise on IMAT reduction.

Main Methods:

• A comprehensive literature search identified RCTs assessing the effect of aerobic training (AET), resistance training (RT), or combined training (COM) on IMAT using noninvasive imaging (MRI/CT).
• Data extraction followed the PICO(T)S framework, and study quality was assessed using the Cochrane risk of bias tool.
• Meta-analysis calculated standardized effect sizes (ES) with 95% CIs, quantifying heterogeneity and exploring subgroup/meta-regression effects, with publication bias assessed via Egger's test.

Main Results:

• Nineteen RCTs involving 962 adults with chronic conditions were analyzed, showing a small overall effect of exercise on reducing IMAT (ES = 0.24).
• Moderate-intensity AET and COM demonstrated greater efficacy in reducing IMAT compared to RT.
• Subgroup analyses indicated larger effects in studies using MRI, in middle-aged versus older adults, and in individuals with HIV compared to other diagnoses.

Conclusions:

• Moderate-intensity aerobic exercise and combined training are effective in reducing IMAT in adults aged 18-65 with chronic diseases, associated with body weight and fat mass loss.
• While exercise generally reduces IMAT, older, frail individuals or those with advanced disease stages may experience paradoxical IMAT accumulation.
• Prescribed exercise, particularly moderate-intensity AET or COM, can reverse the detrimental effects of IMAT on skeletal muscle, highlighting its therapeutic role for physical therapists and healthcare professionals.