High-Intensity Interval Training (HIIT) not only significantly increases the expression of C-C chemokine receptor type 5 (CCR5) in immune cells but also decreases levels of inflammatory mediators such as the Interleukin-6 (IL-6) receptor and Monocyte Chemotactic Protein-1 (MCP-1) in plasma and adipose tissue, potentially ameliorating health issues associated with overweight and obesity. The gene discussed is CCL2; the disease is obesity due to melanocortin 4 receptor deficiency.