There is currently a need for an objective measure to aid in the diagnosis and clinical management of concussion.  Heart rate variability (HRV) is a measure of the autonomic nervous system (ANS) that has recently been used to determine the effects of concussion.  However, research examining HRV and concussion is still in the early stages and the findings remain inconsistent.  The aims of this two-fold study include: 1) identifying differences in HRV measures between athletes with 0, 1,  2 prior concussions, and 2) identifying any HRV differences between concussed athletes, athletes with musculoskeletal injuries, and healthy, control athletes at  7 days post-injury and at 1-month post-injury.  Healthy university athletes (n = 68) completed a 24-hour HRV collection at pre-season.  Concussed athletes (n = 34) and athletes with musculoskeletal injuries (n = 30) completed a 24-hour HRV collection at  7 days post-injury and at 1-month post-injury.  All participants also completed the Post-Concussion Symptom Scale and a Health and Wellness questionnaire.  No significant differences were found in any measures between athletes with 0, 1,  2 prior concussions.  During the acute phase of recovery, the results from the 24-hour HRV recording in concussed athletes are consistent with initial concussion management recommendations.  Furthermore, concussed athletes slept for a longer period of time, however scored worse in the Sleep category of the Health and Wellness questionnaire.  At the 1-month post-injury timepoint, the only significant finding was concussed athletes and athletes with musculoskeletal injuries both had a greater amount of stress reactions (min.) compared to the healthy control group.  Further research is required to investigate this finding.

Examining the effects of concussion on the autonomic nervous system using 24-hour heart rate variability (HRV)