Date of Award

Summer 2023

Document Type

Open Access Thesis


Exercise Science

First Advisor

Robert Davis Moore


OBJECTIVE: The overarching purpose of this study was to investigate the influence of habitual caffeine consumption on mTBI outcomes in adolescents. BACKGROUND: Adolescents who suffer an mTBI have an increased risk for neurological impairment and symptomology. Thus, it is important to elucidate modifiable lifestyle factors that have the potential to influence injury outcomes and recovery. Caffeine is a legal psychoactive compound prevalent among the adolescent population. Marketed as an ergogenic aid caffeine coincides with recreational activities where incidence of mTBI is high. However, no human study has explored the influence of caffeine consumption on mTBI pathology. It was hypothesized that a difference in symptom outcome and recovery would exist between caffeine consumers and non-consumers across a variety of clinical symptom domains and cardio-autonomic function. METHODS: eighty adolescents with mTBI who habitually consume caffeine (CAF+; 38 males, 42 females; 15 ± 2 years) and forty non-consumers (CAF-) were clinically evaluated at a local pediatric concussion clinic on days 13 ± 8 (initial) and 29 ± 11 (follow-up) post injury. The Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Depression subscale of the Beck Youth Inventories - Second Edition (BYI-D), and The Behavior Rating Inventory of Executive Function (BRIEF) were used to subjectively assess somatic, affective, and cognitive symptomatology. Objectively, cardio-autonomic function was assessed via Heart Rate Variability (HRV). RESULTS: A group x time interaction revealed CAF+ had a significantly higher mean score than CAF-for RPQ emotion (p = 0.012) and sleep domains (p = 0.049) at follow-up. In addition, a group main effect indicated CAF+ had a higher RPQ3 score irrespective of time compared to CAF- (p = 0.010). Lastly, CAF+ had a significantly higher mean score than CAF- for depressive symptoms at follow-up (p = 0.015). No significant main effects of group or group x time interactions were reported within the BRIEF or metrics of HRV. CONCLUSIONS: Findings suggest adolescent caffeine consumers may be susceptible to poorer emotional health and sleep quality, and greater somatic discomfort after mTBI in comparison to non-consumers. Offering valuable insight for physicians to better identify pediatric patients who are likely to experience a poorer recovery from mTBI, and in doing improve management strategies. However, additional research is required before recommendations on caffeine consumption can be provided to patients. Until then, adolescents with mTBI should exercise caution towards caffeinated products and alter consumption habits by case relative to symptom diagnosis.