The Energetic Cost Of Concussion: Energy Expenditure Differences Between Adolescents With Concussion And Uninjured Controls

PURPOSE: Concussion-induced pathophysiology creates a state of energy deficiency within the brain. Though physical activity (PA) is recommended to facilitate recovery, the need to balance energy demands after concussion may limit the capacity to engage in PA. How energy expenditure compares between adolescents with and without concussion has not been investigated. METHODS: Adolescent athletes within 18 days of concussion and uninjured athletes wore wrist-worn actigraphy devices for one week to quantify three outcomes: PA (steps/day), caloric expenditure, and resting heart rate (RHR). We examined univariable between-group differences for each outcome using independent samples t-tests, and linear regression models to examine multivariable predictors of each outcome. RESULTS: We enrolled 70 adolescents with concussion (7.9 + 3.4 days post-injury, age = 15.0 + 1.7 years, 54% female) and 64 uninjured controls (age = 15.4 + 1.5 years, 61% female). A higher proportion of the concussion group reported depression history, which was included as a covariate in the regression models. Upon univariable analysis, those with concussion took fewer steps/day than controls (Fig 1A) but caloric expenditure (Fig 1B) and RHR (Fig 1C) did not significantly differ. After adjusting for depression history, the concussion group took fewer steps/day (B = -3179; 95%CI: -4482, -1875; p < 0.001) than controls, despite similar caloric expenditure (B = -187; 95%CI: -377, 3; p = 0.05) and average RHR (B = 1.3 beat/min; 95%CI: -2.4, 5.0; p = 0.50). CONCLUSION: Adolescents with concussion expended similar calories as uninjured controls, despite recording lower PA levels and similar RHR. This may reflect a greater energy demand for individuals with concussion to engage in PA or maintain normal heart rate (i.e., homeostasis) compared to controls. Further research to investigate altered energy needs after concussion may provide therapeutic targets to facilitate recovery.Tai Foundation, Mindsource, Foundation for Physical Therapy Research