BDNF and Anxiety: Consistent with this hypothesis, we found a positive correlation between lactate production in rats in response to EMS and BDNF protein expression in the hippocampus 24 h after the application of the experimental protocol (Pearson correlation, r = 0.8891, p < 0.0001, Figure 8D), while in humans, lactate production was inversely correlated with the decrease in anxiety scores induced by EMS (Pearson correlation, r = 0.8815, p < 0.0038, Figure 8E).