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Updated: Jul 1, 2025

Development of an Uncomplicated Mild Traumatic Brain Injury Model Modified by Weight-Drop Method and Evidenced by Magnetic Resonance Imaging
Published on: April 11, 2025
Symptoms Associated With Exercise Intolerance and Resting Heart Rate Following Mild Traumatic Brain Injury
Jacinta Thorne1, Sarah C Hellewell, Gill Cowen
1Author Affiliations: School of Allied Health (Ms Thorne and Mr Ring) and Curtin Medical School (Drs Cowen, Jefferson, and Xu), Faculty of Health Sciences, Curtin Health Innovation Research Institute (Mss Thorne and Papini and Drs Hellewell, Cowen, Gozt, Pestell, and Fitzgerald), and School of Population Health (Drs Chih, Thomas, and Xu), Curtin University, Bentley, Western Australia; Perron Institute for Neurological and Translational Science, Nedlands, Western Australia (Mss Thorne and Papini and Drs Hellewell, Gozt, and Fitzgerald); Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, Western Australia (Mr Ring); School of Psychological Science (Drs Buhagiar and Pestell) and Divisions of Surgery (Dr Thomas) and Emergency Medicine (Dr Celenza), School of Medicine, The University of Western Australia, Nedlands, Western Australia; Neurological Intervention & Imaging Service of Western Australia (Dr Bynevelt) and Emergency Department (Dr Celenza), Sir Charles Gairdner Hospital, Nedlands, Western Australia; The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China (Dr Xu); Sir Charles Gairdner, Royal Perth and Fiona Stanley Hospitals, Perth, Western Australia (Dr Honeybul); Emergency Medicine, Royal Perth Hospital, University of Western Australia (Dr Fatovich); and Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Nedlands, Western Australia (Dr Fatovich).
Objectives:
People may experience a myriad of symptoms after mild traumatic brain injury (mTBI), but the relationship between symptoms and objective assessments is poorly characterized. This study sought to investigate the association between symptoms, resting heart rate (HR), and exercise tolerance in individuals following mTBI, with a secondary aim to examine the relationship between symptom-based clinical profiles and recovery.
Methods:
Prospective observational study of adults aged 18 to 65 years who had sustained mTBI within the previous 7 days. Symptoms were assessed using the Post-Concussion Symptom Scale, HR was measured at rest, and exercise tolerance was assessed using the Buffalo Concussion Bike Test. Symptom burden and symptom-based clinical profiles were examined with respect to exercise tolerance and resting HR.
Results:
Data from 32 participants were assessed (mean age 36.5 ± 12.6 years, 41% female, 5.7 ± 1.1 days since injury). Symptom burden (number of symptoms and symptom severity) was significantly associated with exercise intolerance ( P = .002 and P = .025, respectively). Physiological and vestibular-ocular clinical profile composite groups were associated with exercise tolerance ( P = .001 and P = .014, respectively), with individuals who were exercise intolerant having a higher mean number of symptoms in each profile than those who were exercise tolerant. Mood-related and autonomic clinical profiles were associated with a higher resting HR (>80 bpm) ( P = .048 and P = .028, respectively), suggesting altered autonomic response for participants with symptoms relating to this profile. After adjusting for age and mechanism of injury (sports- or non-sports-related), having a higher mood-related clinical profile was associated with persisting symptoms at 3 months postinjury (adjusted odds ratio = 2.08; 95% CI, 1.11-3.90; P = .013).
Conclusion:
Symptom-based clinical profiles, in conjunction with objective measures such as resting HR and exercise tolerance, are important components of clinical care for those having sustained mTBI. These results provide preliminary support for the concept that specific symptoms are indicative of autonomic dysfunction following mTBI.
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Exercise Stress Test
Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.
Definition
An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.
Purposes
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...

