Factors associated with energy expenditure and energy balance in acute sport-related concussion

Context: Sport-related concussion (SRC) is characterized by a pathologic neurometabolic cascade that results in an increased intracranial energy demand and a decreased energy supply. Little is known about the whole-body energy-related effects of SRC. Objective: To examine factors associated with whole-body resting metabolic rate (RMR), total energy expenditure (TEE), energy consumption (EC), and energy balance (EBal) in student-athletes acutely after SRC and healthy matched control individuals. Design: Case-control study. Setting: University research laboratory. Patients or Other Participants: Student-athletes diagnosed with SRC (n = 28, 50% female, age = 18.4 ± 1.8 years, body mass index [BMI] = 24.1 ± 4.1 kg/m2) assessed ≤72 hours postinjury and a matched control group (n = 28, 50% female, age = 19.4 ± 2.9 years, BMI = 24.7 ± 4.78 kg/m2). Main Outcome Measure(s): Resting metabolic rate was measured via indirect calorimetry. Participants reported their physical activity and dietary intake for 3 days, which we used to estimate TEE and EC, respectively, and to calculate EBal (EC:TEE ratio). Resting metabolic rate, TEE, and EC were normalized to body mass. Group and group-by-sex comparisons were conducted for RMR-kg-1, TEE-kg-1, EC-kg-1, and EBal using independent t tests with the a priori a = .05. Associations of age, sex, concussion history, BMI, and symptom burden with RMR-kg-1 and EBal were explored with linear regression models. Results: Total energy expenditure-kg-1 was lower (P <.01; mean difference 6 SD=-5.31 6 1.41 kcal-kg-1) and EBal was higher (P < .01; 0.28 6 0.10) in SRC participants than in control participants. Both sexes with SRC had lower TEE-kg-1 than did the control participants (P values - .04); females with SRC had higher EBal than controls (P = .01), but male groups did not differ. Higher RMR-kg-1 was associated with history of concussion (adjusted R2 = .10, β = 0.65). Younger age (β =-0.35), fewer concussions (β =-0.35), lower BMI (β =-0.32), greater symptom duration (β = 1.50), and lower symptom severity (β = -1.59) were associated with higher EBal (adjusted R2 = .54). Conclusions: Total energy expenditure-kg-1 and EBal appeared to be affected by acute SRC, despite no differences in RMR-kg-1. Sex, concussion history, BMI, and symptom burden were associated with acute energy-related outcomes.