Context: Following a sports-related concussion, many athletes experience persisting neurophysiological alterations. These alterations may be absent at rest but emerge during moments of physiological stress. Unnoticed and untreated neurophysiological dysfunction may negatively impact long-term neurological health in adolescent athletes as they are at a critical point in development.

Objective: To assess cardio-autonomic functioning in athletes with and without a history of concussion by quantifying measures of heart rate variability (HRV) during times of physical and mental exertion.

Design: Case-control study.

Setting: Research laboratory

Patients or Other Participants: Thirty-four male midget-AAA hockey players were separated into those with (n = 16, age = 16.1 ± 1 years, BMI = 23.3 ± 1.8) and those without (n = 18, age = 16.0 ±1 years, BMI = 23.6 ± 2.5) a history of concussion.

Intervention(s): All athletes completed a series of HRV recording sessions: 1) at rest; 2) while completing a cognitive task at rest; and 3) while completing a cognitive task after a bout of submaximal aerobic exercise.

Main Outcome Measure(s): Time-domain measures of HRV; mean NN interval (NN), standard deviation of NN interval (SDNN), and root mean square of successive differences (RMSSD) were quantified for each assessment.

Results: Analyses revealed no demographic differences between groups. No between-group differences in HRV at rest, were observed. However, during completion of the cognitive task at rest and following aerobic exercise, athletes with a history of concussion demonstrated significantly higher SDNN (63.2 ± 4.1 vs. 78.1 ± 4.3; 65.2 ± 3.8 vs 71.2 ± 4.3, p = 0.046) and RMSSD (59.0 ± 5.6 vs. 75.8 ± 6.0; 59.0 ± 5.2 vs. 74.0 ± 5.5, p = 0.035).

Conclusion: The results suggest concussive injuries may result in long-term cardio-autonomic dysfunction. Furthermore, these deficits may not be present at rest but may be triggered by physiological stress.

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Author notes

Abbi Lane-Cordova, Ph.D.

Department of Exercise Science

University of South Carolina

921 Assembly Street, 216E

Columbia, SC 29208

Tel: 803-777-3278

Email: lanecord@mailbox.sc.edu

Michael F. La Fountaine, Ed.D., ATC

Department of Physical Therapy

Seton Hall University

123 Metro Boulevard, Room 436

Nutley, NJ 07110

Tel: 973-275-2918

Email: michael.lafountaine@shu.edu

Robert Davis Moore, MS, Ph.D.

Department of Exercise Science

University of South Carolina

921 Assembly Street, 304

Columbia, SC 29208

Tel: 803-777-3278

Email: moorerd3@mailbox.sc.edu