High-Intensity Interval Training with L-Citrulline Malate Reduces NF-κB and HIF-1α Expression and Improves Cardiometabolic Markers in Obese Middle-Aged Women

Background: Obesity in midlife women is accompanied by chronic low-grade inflammation and tissue hypoxia mediated by transcription factors such as nuclear factor-κB (NF-κB) and hypoxia-inducible factor-1α (HIF-1α). High-intensity interval training (HIIT) improves cardiometabolic health, while L-citrulline malate (CM) enhances nitric oxide (NO) production and endothelial function. This study examined the combined effects of HIIT and CM on NF-κB and HIF-1α expression and related metabolic and inflammatory outcomes in obese middle-aged women. Methods: Forty participants were randomized to Control (n = 13), HIIT (n = 13), or HIIT + CM (n = 14) groups for eight weeks. HIIT consisted of three supervised sessions per week (80–85% VO₂max). The supplemented group received oral L-citrulline malate according to protocol. Primary endpoints were PBMC gene expression of NF-κB and HIF-1α. Secondary outcomes included plasma monocyte chemoattractant protein-1 (MCP-1), malondialdehyde (MDA), superoxide dismutase (SOD) activity, fasting lipid profile, and visceral adipose tissue (VAT) area. Results: Both HIIT and HIIT + CM significantly downregulated NF-κB (−17.5% and −26.2%) and HIF-1α (−13.5% and −20.1%) versus control (p < 0.01), with stronger responses in the supplemented group. MCP-1 (−18.8 pg/mL), MDA (−0.53 μmol/L), LDL-C (−18.6 mg/dL), and triglycerides (−34.7 mg/dL) decreased, while SOD (+0.32 U/mL) and HDL-C (+3.1 mg/dL) increased significantly. VAT area declined in both active arms. Conclusion: Eight weeks of HIIT effectively improved inflammatory, oxidative, and lipid markers in obese women. L-citrulline malate supplementation further enhanced reductions in NF-κB and HIF-1α expression, suggesting synergistic benefits through NO-mediated anti-inflammatory and hypoxia-ameliorating mechanisms.