Bone and Joint Institute
Concussion in Adolescents Impairs Heart Rate Response to Brief Handgrip Exercise
Document Type
Article
Publication Date
9-1-2020
Journal
Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine
Volume
30
Issue
5
First Page
e130
Last Page
e133
URL with Digital Object Identifier
10.1097/JSM.0000000000000635
Abstract
OBJECTIVE: Test the hypotheses that (1) concussion in adolescents impairs autonomic neural control of heart rate (HR), and (2) HR reactivity improves with symptom resolution. DESIGN: Observational, case-control. PARTICIPANTS: Nineteen concussed adolescents (8 female adolescents; age 15 ± 2 years) and 16 healthy controls (6 female adolescents, age 15 ± 2 years). INTERVENTION: All participants performed an isometric handgrip (IHG) at 30% maximum voluntary contraction lasting 30 seconds. Heart rate (electrocardiogram) and hemodynamic responses (photoplethysmographic Finometer) were recorded from 30 seconds of baseline and the last 10 seconds of handgrip. MAIN OUTCOME MEASURES: The HR response (ΔHR) at the onset of moderate-intensity IHG using a mixed 1-way analysis of variance. RESULTS: A group × time interaction (P < 0.005) indicated that handgrip evoked a greater ΔHR among control participants (13 ± 10 beats/min) compared with concussed (6.4 ± 6.3 beats/min; group P = 0.63; time P < 0.001; d = 0.77). CONCLUSION: These preliminary results suggest that a concussion impairs the ability to elevate HR at the exercise onset and, given the nature of the task, this could be interpreted to reflect reduced ability to withdraw cardiovagal control. Therefore, the data support the hypothesis of neural cardiac dysregulation in adolescents diagnosed with concussion. CLINICAL RELEVANCE: The IHG test could aid concussion diagnosis and support return-to-play decisions.
