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

## TL;DR

This study found that athletes with ADHD have higher baseline levels of TCA cycle metabolites, and head impacts cause mitochondrial dysfunction in both ADHD and non-ADHD athletes.

## Contribution

The novel finding is that ADHD is associated with elevated baseline TCA metabolites and greater post-impact mitochondrial disruption.

## Key findings

- ADHD athletes had higher baseline levels of TCA cycle metabolites like oxaloacetate and citrate.
- Head impacts caused significant decreases in TCA metabolites, more pronounced in ADHD athletes.
- Pyruvate, alpha-ketoglutarate, and fumarate levels increased after head impacts in both groups.

## 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.

•Individuals with ADHD exhibit elevated baseline levels of Krebs cycle metabolites•Ten headers altered most mitochondrial metabolites regardless of ADHD•Byproducts of Krebs cycle metabolites were also elevated after ten headers

Individuals with ADHD exhibit elevated baseline levels of Krebs cycle metabolites

Ten headers altered most mitochondrial metabolites regardless of ADHD

Byproducts of Krebs cycle metabolites were also elevated after ten headers

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