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Reduced Resting and Increased Elevation of Heart Rate Variability With Cognitive Task Performance in Concussed Athletes

Huang, Mu, DPT; Frantz, Justin, BS; Moralez, Gilbert, PhD; Sabo, Tonia, MD; Davis, Peter F., MD; Davis, Scott L., PhD; Bell, Kathleen R., MD; Purkayastha, Sushmita, PhD

The Journal of Head Trauma Rehabilitation: January/February 2019 - Volume 34 - Issue 1 - p 45–51
doi: 10.1097/HTR.0000000000000409
Focus on Clinical Research and Practice

Objective: To examine heart rate variability (HRV) at rest and with a 2-Back cognitive task involving executive function and sustained attention in athletes during the acute phase following concussion and compare them with the controls.

Participants: Twenty-three male and female collegiate athletes (20 ± 1 years) following (4 ± 1 days) a sports-related concussion and 23 sports- and sex-matched noninjured controls.

Procedure: Continuous R-R interval was acquired using 3-lead electrocardiogram for 3 minutes each at rest and during the 2-Back task. HRV was quantified as percent high-frequency (HF) power.

Results: At rest, lower percent HF power was observed in the concussed athletes (23 ± 11) compared with the controls (38 ± 14; P = .0027). However, with the 2-Back task, an increase in HF power was observed in the concussed group (39 ± 12; P = .0008) from rest and was comparable with the controls (36 ± 15). No difference in HF power between rest and 2-Back task was observed in the controls.

Conclusion: Lower HRV was observed at rest following concussion. An increase in HRV, suggestive of enhanced prefrontal cortex (PFC) functioning, was observed during a cognitive task in the concussed athletes. Therefore, cognitive tasks as early as 4 days after injury may increase PFC functioning from rest and expedite return to learn in collegiate athletes.

Department of Applied Physiology and Wellness, Simmons School of Education and Human Development (Drs Huang, S. L. Davis and Purkayastha and Mr Frantz), and Dr Bob Smith Health Center (Dr P. F. Davis), Southern Methodist University, Dallas, Texas; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (Dr Moralez); Departments of Pediatrics/Division of Pediatric Neurology & Pain Management (Dr Sabo) and Physical Medicine and Rehabilitation (Dr Bell), University of Texas Southwestern Medical Center, Dallas.

Corresponding Author: Sushmita Purkayastha, PhD, Department of Applied Physiology and Wellness, Simmons School of Education and Human Development, Southern Methodist University, 3101 University Blvd, Dallas, TX 75205 (

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The authors declare no conflicts of interest.

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