Motivation: Given lactate's role as an energy metabolite of the brain via the lactate shuttle hypothesis, the accumulation and clearance of lactate in brain diseases is not well understood. In this work, we show lactate elevation in the healthy human brain after intense exercise and calculate a lactate recovery time constant (ΤLac). Goal(s): To quickly detect lactate + threonine (Lac+) signal and measure its clearance post-exercise. Approach: Measure baseline and post-exercise Lac+ with 1H-MRS. Results: Lac+/Water ratios increased 2.0 - 5.1 times their baseline values with sub>ranging between 18-52 minutes across participants. Impact: Brain Lac+/Water clearance can be measured in healthy humans after intense-exercise. While the blood lactate literature suggests that larger increases in lactate correlate with faster recovery times, our results indicate that brain Lac+ recovery may be influenced by additional factors.
Armbruster et al. (2025) studied this question.