Concussion recovery exemplifies the complexity of the brain-heart connection. When the brain is injured, the effects often extend to cardiovascular function through disrupted autonomic pathways that regulate heart rate, blood pressure, and other vital functions. This presents challenges but also opens research opportunities for more effective concussion treatments across all ages. Led by Dr. Roger Zemek, this BHI research is uncovering these critical relationships and translating discoveries into practical interventions to transform patient care.
Concussion Care Guided by Research
Concussions affect nearly 400,000 Canadians each year, yet the majority of research has focused on high-performance athletes and military personnel, leaving many patients with mixed results from current care options. Sponsored by the BHI, a research team led by Dr. Roger Zemek is exploring how exercise and cardiovascular health can help reduce concussion symptoms in non-athlete adults. Using exercise as a therapeutic approach could offer a practical, affordable way to shorten recovery and speed up return to usual daily lives.
Dr. Zemek is a pediatric emergency physician and senior scientist at the Children’s Hospital of Eastern Ontario (CHEO), a full Professor and Tier-1 Clinical Research Chair at University of Ottawa, and Scientific Director of 360 Concussion Care – a network of interdisciplinary concussion clinics operating as a Learning Health System. Among a talented research team that includes Dr. Sharon Johnston, a clinical researcher and Scientific Director and Associate Vice-President at Institut du Savoir Montfort, Dr. Nick Reed, an occupational therapist at the University of Toronto, and over 25 world-leading concussion experts, Dr. Zemek leads the TRANSCENDENT Concussion Research Program that is dedicated to improving concussion diagnosis, prognosis, and care. This program aims to collect the largest openly available dataset on concussions to date. This dataset, collected across the network of 360 Concussion Care clinics in Ontario, will represent a diverse patient group spanning age, sex, and cause of concussion (1).
Investigating the Brain-Heart Connection in Concussions
Through the BHI-funded project, Dr. Zemek and his team are investigating the link between autonomic dysfunction and persistent symptoms following concussion. The autonomic nervous system – controlled primarily by the brainstem – regulates involuntary functions like heart rate, blood pressure, and breathing. When disrupted, it can cause symptoms such as headaches, light and noise sensitivity, dizziness, anxiety, and sleep disturbances; all of which are also common after concussion, especially during physical activity or changes in posture (e.g., moving from lying to standing). These symptoms may result from impaired brain-heart communication due to neural pathway disturbances following concussion. In a pilot study of 451 adults with a recent concussion, Dr. Zemek’s team found that 25% had some type of autonomic dysfunction.
The role of autonomic dysfunction in concussion recovery remains poorly understood, particularly among non-athlete adults, a population that is underrepresented in this area of brain-heart interaction research. In prior studies, these researchers have demonstrated that exercise can improve concussion symptoms in pediatric patients (2); however, this potential benefit has not yet been investigated in adult populations. To address this gap, the current study investigates whether exercise can improve both concussion symptoms and quality of life in adults recovering from concussion.
Over the past two years, the research team has been enrolling adults aged 18 to 85 who have recently sustained a concussion. Participants undergo comprehensive physiological assessments to evaluate autonomic function, including tilt-table testing, continuous heart rate monitoring, pupillometry, eye-tracking, advanced neuroimaging, and biochemical analyses of saliva samples. To date, the study has nearly completed recruitment, with over 400 participants enrolled.
Each participant performs a graded exercise test on a stationary bicycle in a clinical setting and is prescribed an individualized daily exercise plan based on their heart rate response. Throughout the study, participants are monitored for concussion symptoms, quality of life, cardiovascular function, daily activity, and exercise tolerance via repeat bike testing. If the hypothesis is supported—that daily, heart rate-guided exercise facilitates faster recovery and improves quality of life—this would provide evidence for an accessible, low-cost, non-pharmacological intervention for concussion treatment in the general adult population. This project exemplifies the foundation of BHI research and contributes to its growing body of work on therapies for brain-heart conditions, including investigations into how biological and lifestyle interventions can be used to treat these conditions at an early stage.
Autonomic Dysfunction in Pediatric Concussions
In parallel with these ongoing prospective studies, the team is also analyzing previously collected concussion data to further advance understanding in the field. Dr. Veronik Sicard, a post-doctoral fellow at the CHEO Research Institute working alongside Dr. Zemek, recently published a study in JAMA Network Open examining the relationship between autonomic dysfunction (specifically changes in heart rate and blood pressure) and the worsening of concussion symptoms during postural changes in children aged 5 to 17 (3). Published in July 2025, the study found that approximately 10% of pediatric participants exhibited abnormal cardiovascular responses (in either heart rate or blood pressure), and 25% experienced worsening of their concussion symptoms, upon moving to an upright position.
A key and unexpected finding from Dr. Sicard’s study was that autonomic dysfunction and symptom worsening upon standing rarely occurred in the same individuals. Despite both being relatively common, this suggests they may reflect distinct and independent physiological mechanisms. As Dr. Sicard explains, “This work raised the possibility that distinct mechanisms underlie autonomic changes and symptom provocation, which explain why they rarely co-occur. This dissociation warrants investigation into whether physiological versus symptom-driven presentations reflect different recovery pathways or concussion subtypes.”
These findings challenge existing assumptions about symptom patterns in pediatric concussions and highlight the importance of comprehensive clinical assessment to guide more individualized care. Dr. Sicard’s future work, aligned with the BHI project outlined above, will further explore whether similar patterns are seen in adults and older adults, with the goal of developing age-specific intervention strategies. “Our BHI project looks at whether these factors can help predict recovery, helping to identify individuals at risk for prolonged recovery,” she adds.
Implementation of BHI Cross-Cutters in Concussion Research
A foundation of the BHI is the integration of cross-cutter enablers in all research. Dr. Zemek’s team has been exemplary in integrating numerous BHI cross-cutters, including co-production and knowledge mobilization, open science, and IDEAS, which increases the global impact of this research. A core pillar of the TRANSCENDENT project is its strong knowledge mobilization strategy, grounded in patient engagement. Their Community Advisory Committee, comprising individuals with lived experience of concussion from diverse backgrounds, meets quarterly to guide all aspects of the program, from research design to clinical implementation. This ensures that patient voices remain central to both the BHI project and the TRANSCENDENT program, supporting their sustained integration in research.
The team is a leader in knowledge mobilization, translating their research findings into clear, accessible, practical resources. Their website hosts a quarterly newsletter featuring research highlights, upcoming events, and links to their community handouts on topics such as return-to-camp guidelines and concussion support for coaches, teachers, and parents. It also includes recorded talks from experts onvarious aspects of concussion care (4).
Importantly, equity, diversity, and inclusion are embedded in every aspect of Dr. Zemek’s research. The team actively promotes participation from all backgrounds and underrepresented groups to support equitable representation in research findings and access to appropriate care. For example, by ensuring that all intake appointments are in-clinic and covered by OHIP, they help to remove financial and systemic barriers to study participation and access to care.
Data Sharing and Global Reach
Dr. Zemek and his team are committed to open science. All data generated through the TRANSCENDENT program and related projects will be made publicly available. Research findings will be published in open-access journals, and raw data, including physiological measures, biological samples, and detailed symptom and demographic questionnaires from a projected 5,500 concussion patients, will be uploaded to the publicly accessible Brain-CODE platform. As of August 2025, 2,018 patients have already been enrolled (5). This open data approach will enable researchers worldwide to explore new insights for years to come, positioning Ottawa as a global leader in evidence-based concussion care.
The team has already made strides in how concussions are assessed and managed, with much more to come. Their ongoing research projects, including the BHI-funded exercise study, will have significant impact, transforming concussion diagnosis and treatment globally. By leveraging large-scale datasets, and exploring exercise and cardiovascular health as potential therapies, their work supports a shift toward precision, accessibility, and patient-centered concussion care. Ultimately, this research is contributing to the concussion management knowledge base that will be used to help people – across Ontario and beyond - recover faster and return to daily life with improved quality and function.
To learn more about the TRANSCENDENT research program and stay up-to-date on the latest developments in concussion research, please click here.
References
1. Zemek R, Albrecht LM, Johnston S, Leddy J, Ledoux AA, Reed N, et al. TRANSCENDENT (Transforming Research by Assessing Neuroinformatics across the Spectrum of Concussion by Embedding iNterdisciplinary Data-collection to Enable Novel Treatments): protocol for a prospective observational cohort study of concussion patients with embedded comparative effectiveness research within a network of learning health system concussion clinics in Canada. BMJ Open. 2025 Apr;15(4):e095292.
2. Ledoux AA, Barrowman N, Bijelić V, Borghese MM, Davis A, Reid S, et al. Is early activity resumption after paediatric concussion safe and does it reduce symptom burden at 2 weeks post injury? The Pediatric Concussion Assessment of Rest and Exertion (PedCARE) multicentre randomised clinical trial. Br J Sports Med. 2022 Mar;56(5):271–8.
3. Sicard V, Irani T, Ledoux AA, Terekhov I, Webster RJ, Sucha E, et al. Prevalence of Orthostatic Autonomic Dysregulation in Pediatric Concussion. JAMA Netw Open. 2025 July 22;8(7):e2522309.
4. Resources [Internet]. TRANSCENDENT Concussion Research Program. 2025 [cited 2025 Sept 4]. Available from: https://www.transcendentconcussion.ca/outreach
5. Research Participants [Internet]. TRANSCENDENT Concussion Research Program. 2025 [cited 2025 Aug 26]. Available from: https://www.transcendentconcussion.ca/participants