Effect of Acute Exercise on P300 Event-Related Potential and Its Correlation With Blood Lactate Levels

Introduction Acute exercise can transiently enhance cognition. Lactate produced during aerobic exercise may cross the blood-brain barrier and influence neuroplastic pathways, potentially modulating P300 event-related potential (ERP) indices. Materials and methods In this pre-post interventional study conducted at Indira Gandhi Institute of Medical Sciences, in Patna, India (IEC approval number: 767/IEC/IGIMS/2022), 50 healthy male participants (18-40 years) underwent exhaustive aerobic exercise (Bruce protocol). Blood lactate was measured using the Sensa Core Lacto Spark point-of-care testing (POCT) (Sensa Core Medical Instrumentation Pvt. Ltd., Hyderabad, India). Auditory P300 ERPs were recorded at baseline, immediately post-exercise, 10 minutes post-exercise, and 20 minutes post-exercise, using a four‑channel MEP Neurosoft system (Neurosoft, Ivanovo, Russia) with 10-20 montage (Fpz ground, Cz active, M1/M2 reference) and 0.01-30 Hz bandpass. The oddball paradigm used 1000 Hz standard and 2000 Hz target tones (probabilities 0.80/0.20; sound pressure level (SPL) 60 dB; 10 ms rise/fall; 50 ms plateau). Outcomes included P300 latency, N2P3 amplitude, mean reaction time (MRT), true-click %, and false-click %. Analyses included repeated‑measures ANOVA with Bonferroni post hoc tests, Shapiro-Wilk for normality, Pearson correlation, and linear regression (IBM SPSS Statistics for Windows, Version 29.0.2.0 (IBM Corp., Armonk, New York, United States)). Results Lactate rose from 1.89±1.34 mmol/L (pre) to 6.91±2.24 mmol/L (immediate post) and declined at 10 minutes (4.80±1.72) and 20 minutes (3.43±1.31). P300 latency decreased significantly immediately after exercise when compared to the baseline (F=12.385; p<0.001); N2P3 amplitude increased (F=16.070; p<0.001); MRT decreased (F=8.007; p<0.001). Pairwise comparisons showed significantly shorter latency at all post-exercise time points vs. baseline; N2P3 amplitude was higher immediately post-exercise and lower at 20 minutes vs. baseline. True-click % increased immediately post (p=0.040), and false-click % decreased at 10 minutes (p=0.023). Lactate rise correlated positively with N2P3 amplitude (Pearson p<0.05), but the regression model did not reach significance (R²=0.072; p=0.059). Conclusion Acute exhaustive exercise significantly enhanced cognitive efficiency, reflected by reduced P300 latency, increased N2P3 amplitude, and faster reaction times. The association between lactate rise and ERP changes highlights its potential role as a biomarker and therapeutic target for exercise-induced cognitive benefits. These findings open avenues for clinical translation, where lactate-focused interventions and structured exercise regimens may be explored with cognitive performance and support rehabilitation strategies.