Alterations in mitochondrial energy metabolites following acute subconcussive head impacts among athletes with and without ADHD

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is prevalent among contact sports athletes, who may regularly incur repetitive head impacts. This study investigated the effects of acute head impacts on mitochondrial function by analyzing tricarboxylic acid (TCA) cycle metabolites and the potential modulatory role of ADHD. Fifty adult soccer players (ADHD n = 25; non-ADHD n = 25) participated, undergoing ten soccer headers using a controlled heading model. TCA metabolites were assessed at pre-heading baseline, and 2 and 24 h post-heading. Baseline analysis revealed elevated levels of TCA metabolites, including oxaloacetate, citrate, and isocitrate, in the ADHD group. Following head impacts, both groups exhibited significant decreases in these metabolites, yet the magnitude of decrease was more pronounced in the ADHD group. Pyruvate, alpha-ketoglutarate, and fumarate levels increased after headers in both groups. These findings suggest that ADHD is associated with elevated baseline metabolites initiating the TCA cycle, while acute head impacts induce mitochondrial dysfunction, regardless of ADHD.