Reference: Am J Sports Med. 2018 Mar;46(3):743-752 (level 2 [mid-level] evidence)
Two and a half million concussions are reported each year among high school students in the United States (MMWR Surveill Summ. 2018 Jun 15). Until recently, treatment advice consisted of physical and mental rest until symptoms resolved (PM R. 2016 Mar; J Head Trauma Rehabil. 2013). Specific indications for return to play are often vague (CDC). Consider a 16-year-old female cheerleader who presents, after hitting her head on the ground, with headaches, difficulty concentrating, and intermittent blurry vision. Should she simply sit out of both school and physical exercise for a minimum of 2 weeks or until her symptoms completely resolve, or should she exercise her brain back into shape? Is physical and mental rest better than activity post-concussion?
A systematic review of 14 studies (5 randomized trials, 4 cohort studies, 5 before-and-after studies) compared exercise to control (either no exercise or physical rest) in patients following a concussion or mild traumatic brain injury within the last 3 months. Of the 14 studies, 10 evaluated sports-related concussions. Studies evaluating moderate and severe traumatic brain injuries were excluded. Three validated scoring systems were used, including the Post-Concussive Symptom Scale (PCSS) (Clin J Sport Med. 2001 Jan; Clin Neuropsychol. 2003 Nov), the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) (ClinNeuropsychol. 2010 Nov; Brain Inj. 2011), and the Balance Error Scoring System (BESS) (Neurology. 2013Jun 11). The meta-analysis accounted for publication bias and variability between studies.
Physical exercise was associated with improvement in the PCSS score compared to control (mean difference 13.06 points, 95% CI 9.55-16.57) in analysis of 8 studies with 176 patients, but results were limited by significant heterogeneity. Consistent results were seen in subgroup analyses by patient population (including patients with sports-related concussion, adolescents with concussion, and adults with concussion) and time since injury (< 5 days, mean 11 days, and 21-90 days). Compared to control, physical exercise was also associated with a reduction in patients with symptoms (risk ratio 0.74, 95% CI 0.63-0.86) in analysis of 3 studies with 1,255 patients and a reduction in missed work days (mean difference 14.5 days, p < 0.05) in 1 randomized trial with 178 patients. There were no significant differences in ImPACT scores comparing physical exercise to control in analysis of 3 studies with 286 adolescents with sports-related concussion. In single trials comparing physical exercise to control, physical exercise was associated with reduced duration, severity, and frequency of symptoms in 58 adults with acute concussion, and improvement in visual memory and reaction time from baseline in 88 patients with recent concussion. Notably, high intensity exercise was shown to worsen visual memory and reaction time compared to controls while light and moderate intensity exercised improved these components in separate RCTs (p < 0.007 and p = 0.01, respectively).
This systematic review suggests that physical exercise following a concussion may improve concussion symptoms, visual memory, and reaction time, and may reduce the duration of symptoms following a concussion. The results are limited by heterogeneity of interventions and outcomes assessed as well as by the limitations of subgroup analyses. There are few available RCTs on this subject to include in this meta-analysis. Therefore, the results inherently rely on cohort and before-and-after studies, which carry less statistical clout. Still, these data support starting low- to moderate-intensity exercise 24-48 hours after a concussion may have better outcomes than complete rest. Future randomized controlled trials will help to strengthen this conclusion.
For more information, see the topic Concussion and Mild Traumatic Brain Injury in DynaMed.
Phillip Sasser III M.D., M.Sc.
Phillip is a 3rd year resident in the University of Virginia Family Medicine Residency program with interests in sports medicine, wilderness medicine, and preventative medicine.
Faculty contributions by Dr. Katharine DeGeorge