Lactate as a Cognitive Enhancer: Effects of Exercise-Induced Lactic Acid Elevation on Working Memory and Inflammatory Markers in Older Adults with Mild Cognitive Impairment (MCI)

This study investigates the multifaceted role of exercise-induced lactate elevation in enhancing cognitive function and reducing neuroinflammation in older adults with Mild Cognitive Impairment (MCI). Cognitive decline, particularly MCI, represents a critical transitional phase between normal aging and dementia, characterized by reductions in memory and other cognitive domains without significantly impairing daily functioning. While pharmacotherapies have limited efficacy and adverse effects, non-pharmacological approaches like physical exercise are gaining recognition as complementary strategies. Exercise significantly improves cerebral blood flow, boosts neurogenesis, and induces neurotrophic factors like Brain-Derived Neurotrophic Factor (BDNF). Lactate, traditionally seen as a mere byproduct, is now understood as a neuromodulatory molecule that crosses the blood-brain barrier via monocarboxylate transporters (MCTs). Within the central nervous system, lactate acts as both a metabolic substrate and a signaling molecule, upregulating BDNF, IGF-1, and VEGF, which are crucial for synaptic plasticity, memory formation, and neurogenesis in regions like the hippocampus and prefrontal cortex. Moreover, lactate demonstrates anti-inflammatory effects by suppressing pro-inflammatory signaling, leading to observed reductions in IL-6, TNF-α, and CRP levels following exercise interventions. The methodology involves a randomized controlled trial with aerobic, combined aerobic and resistance exercise, and control groups, recruiting 75 MCI participants aged 60-75. Outcome measures include neuropsychological tools for cognitive function, venous blood samples for lactate, and ELISA for inflammatory biomarkers. This review underscores lactate as a central neuro-metabolic regulator, capable of dual action in enhancing cognitive function and decreasing inflammation, thus proposing lactate-targeted interventions as a promising biomarker-driven strategy for delaying neurodegeneration. The observed cognitive improvements and decreases in inflammatory markers after mid-to-high intensity exercise align with this lactate-driven model. Future research should integrate frequent lactate monitoring and personalized training protocols.