The added benefit of SSTAE to treatment-as-usual did not lead to greater reduction in symptom burden compared to the control group, however SSTAE significantly improved exercise intolerance and was safe and well tolerated.
Key Findings
Results
Sub-symptom threshold aerobic exercise (SSTAE) did not significantly reduce postconcussion symptom burden compared to treatment-as-usual at 12 weeks or 6 months.
Primary outcome was symptom burden measured with the Rivermead Post-Concussion Symptoms Questionnaire (RPQ)
No between-group differences were observed in the RPQ at either the 12-week or 6-month follow-up timepoints
Both groups improved over time in symptom burden, suggesting natural recovery or non-specific effects of treatment-as-usual
The trial was a randomized (1:1) controlled single-blind, parallel-group design with 81 adults aged 18–59 years
Results
SSTAE significantly improved exercise intolerance as measured by symptom threshold on the Buffalo Concussion Treadmill Test (BCTT) at 12 weeks, with effects sustained at 6 months.
The secondary outcome of exercise intolerance was measured as the symptom threshold and minutes to stop on the Buffalo Concussion Treadmill Test
SSTAE group showed significant improvement in BCTT symptom threshold at 12 weeks compared to the control group
The improvement in BCTT symptom threshold was sustained at the 6-month follow-up
The SSTAE group was also superior to the control group in minutes to stop at 12 weeks, but this difference was not maintained at 6 months
Results
SSTAE was safe and well tolerated, with no adverse events occurring in either group.
No adverse events were reported across the intervention period
Participants were adults with persistent postconcussion symptoms and exercise intolerance 3 to 24 months after mild traumatic brain injury
The intervention was described as 'symptom restricted aerobic exercise provided by a physical therapist'
Safety was monitored throughout the 12-week intervention and 6-month follow-up period
Results
No statistically significant between-group treatment effects were observed for any tertiary outcomes including health-related quality of life, depression, anxiety, fatigue, or level of physical activity.
Tertiary outcomes included measurements of health-related quality of life, depression, anxiety, fatigue, and level of physical activity
No statistically significant treatment effects were observed for any of these tertiary outcomes
Despite no between-group differences, both groups improved over time in health-related quality of life, depression, anxiety, and fatigue
This pattern of within-group improvement without between-group differences suggests both interventions may contribute to improvement or that natural recovery accounts for the gains
Methods
The study enrolled adults aged 18–59 years with persistent postconcussion symptoms and exercise intolerance occurring 3 to 24 months after mild traumatic brain injury.
81 participants were randomized in a 1:1 ratio to SSTAE plus treatment-as-usual versus treatment-as-usual with general exercise information and advice only
The setting was a TBI outpatient clinic at Oslo University Hospital, Norway
Inclusion required both persistent postconcussion symptoms and exercise intolerance, assessed via the Buffalo Concussion Treadmill Test
Follow-up assessments occurred at 12 weeks and 6 months after randomization
Background
Prior research on aerobic exercise for postconcussion symptoms had been predominantly conducted in adolescent athletes, and this trial addressed the gap of evidence in adults with persistent postconcussion symptoms.
The authors noted that 'the effects of aerobic exercise on PCS in adolescent athletes have been promising'
The authors identified that 'randomized controlled trials targeting persistent PCS in the adult population are needed'
Persistent postconcussion symptoms following mild traumatic brain injury are described as 'common and often associated with exercise intolerance'
The study targeted a chronic phase population (3–24 months post-injury) rather than acute or subacute presentations
What This Means
This research suggests that a structured, supervised aerobic exercise program kept below the level that triggers symptoms — called sub-symptom threshold aerobic exercise (SSTAE) — can meaningfully improve the ability to exercise without worsening symptoms in adults who have had persistent concussion symptoms for months after a mild brain injury. In this Norwegian clinical trial of 81 adults, those who received guided aerobic exercise in addition to standard care were able to exercise longer and at higher intensities before hitting their symptom threshold, compared to those who only received standard care plus general advice about exercise. Importantly, the exercise program was safe, with no adverse events reported.
However, the exercise program did not lead to greater overall reductions in concussion-related symptoms — such as headaches, dizziness, and cognitive difficulties — compared to standard care alone. Both groups showed improvement in symptom burden, quality of life, depression, anxiety, and fatigue over the course of the study, suggesting that standard outpatient care and the natural passage of time may contribute substantially to recovery regardless of whether structured aerobic exercise is added.
This research matters because many people with persistent concussion symptoms avoid physical activity out of fear of making their condition worse, yet exercise intolerance itself can become a barrier to recovery. The finding that a supervised aerobic exercise program — delivered by a physical therapist — safely improves exercise tolerance in this population is clinically meaningful, even if it does not directly reduce symptom burden beyond what standard care already provides. Future research may need to investigate whether specific subgroups benefit more, or whether longer or more intensive programs could produce broader symptom relief.
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