Engaging In Exercise After Concussion May Actually Help Speed Recovery In Teens, Study Finds

A new study challenges the widespread recommendation for complete physical rest in the period immediately after concussion and for limiting physical activity until an athlete is no longer experiencing severe symptoms, finding no link between the level of physical activity and length of concussion recovery, and that engaging in exercise may actually help speed recovery in adolescents. 

Analyzing survey data gathered from a 364 patients seen in a concussion clinic within 3 weeks of injury and at follow-up visits, researchers at Boston Children’s Hospital found no association between physical activity after injury and recovery time for the group as a whole, but that higher levels of physical activity after injury were associated with shorter recovery times for study participants aged between 13 and 18 years.

The study was published online in the journal Pediatrics. 

“The lack of association between the amount of physical activity  during the course of recovery and symptom duration among [all 364 participants] suggests that some amount of physical activity may be acceptable during recovery from concussions,” said the study’s lead author, David Howell of The Micheli Center for Sports Injury Prevention and the Sports Concussion Clinic at Boston Children’s.  

That higher levels of physical activity were linked to faster recoveries for adolescents, while such an association was not found for the older or younger age groups, Howell said, also “indicates that physical activity may affect symptom recovery throughout each stage of development differently, and that adolescents may benefit from physical activity to decrease symptom resolution time.”

The relationship between physical activity after concussion and symptom duration, though increasingly studied in recent years, remains unclear. Relying on studies reporting a relationship between a premature return to physical activity after concussions and increased concussion symptoms, and others finding that such activity did not allow for full recovery of postural stability (e.g. the ability to control a body’s movement in space), some have argued that unrestricted physical activity after concussion should be avoided.

Others have argued against prescribing complete avoidance of physical activity after concussion based on studies finding that the lack of exercise increases anxiety and depression and to lower self-esteem in concussed athletes, and a recent study reporting that adolescents who rested completely for the first five days after concussion reported higher symptoms over the first ten days after injury than those who only rested the first 1- to 2-days after concussion.

The results of the current study, said Howell, suggest not only that “complete physical rest may not be an effective treatment strategy after concussion,” but that physical activity does not lengthen the time required for a patient to become asymptomatic, particularly among adolescent athletes. Noting that the results of the current study were also consistent with previous studies showing that patients suffering from a traumatic brain injury who exercise are less depressed, report fewer symptoms, and have a better health status than non-exercising patients, Howell and his colleagues argue that a closely monitored program of physical activity after concussion may potentially lead to decreased symptom severity and shorter recovery times. 

Such a recommendation, they say, is also supported by studies finding that exercise at mild-to-moderate intensities may improve cerebrovascular function, which can be damaged as a result of concussion and may, at least partly, underlie concussion symptoms such as altered cognitive function, headache, or dizziness.

Finally, the study also notes that, particularly among athletes, a lack of physical activity may lead to deconditioning, which can impair blood flow in the brain, with a decrease in cerebrovascular function having been documented after deconditioning caused by sustained head-down bed rest, and in a study showing that even a single day of bed rest results in a short-term reduction in cerebral blood flow. “Thus,” Howell theorizes, “those who continue to engage in physical rest beyond the acute phase of concussion recovery may be at risk for deconditioning, which may lead to a longer duration of time required for symptom resolution.”

Because the participants in the current study were primarily athletes, Howell and his colleagues note that athletes may benefit from the addition of physical activity after a concussion because it represents “a return to normal everyday life. As athletes who miss time due to injury may be more likely to exhibit depression or anxiety, symptoms also associated with concussions, some physical activity for this population may constitute a potential treatment to assist with the reduction of emotional symptoms,” he suggests.

The study’s findings, says Howell, “warrant further investigation regarding the effects of physical activity after the injury on recovery from concussions.” In particular, he said, “the effects of intensity level and timing of physical activity on recovery from a concussion should be further explored.” 

Ceiling effect for rest?

“I appreciate this new contribution to the research literature which provides more knowledge as well as questions regarding rest and activity following concussion,” said Rosemarie Scolaro Moser, a sports neuropsychologist and Director of the Concussion Center of New Jersey.

“Importantly, the authors indicate that 76% of the study participants completed a rest period prior to being seen at the clinic.  And then, at the second clinic visit, 29% were still reporting ‘complete rest.’  So it looks like there was a lot of resting going on after concussion. And we don’t have an analysis of symptoms at the time of concussion vs. after their period of rest.”

“It may be that this study is telling us more about a ‘ceiling effect’ with rest, meaning that once rest is engaged in, then mild activity may not be detrimental to the athlete. I think we clinicians already know intuitively that no one should be placed on indefinite rest following a concussion.  But it is important to include rest initially, and then to ease into activity and re-conditioning.  I believe readers of this research should not jump to the conclusion that there is no need for rest.  The authors are not making that proclamation.” 

“The authors do point out that the activity was ‘self-selected’, so we don’t know what kind of activity was engaged in or to what degree,” noted Moser.  Furthermore, a closer look at age differences may shed further light on the activity level since the age range was from 8 to 27 years.  And it would be interesting to examine sex differences in recovery with activity, since there were many more males than females, as is often the case in concussion research. “

“In this study, 68% recovered.  So how do the 32% fair?  We need research that can separate those cases that heal easily from those that remain persistent.  My guess is  the formula for optimal rest and optimal activity may vary depending on the severity level.  We have a long way to go before we have a handle on all the variables that affect concussion recovery,” Moser concluded. 

Study details

This study included 364 patients who were diagnosed with a concussion and seen in the Boston Children’s concussion clinic within 3 weeks of injury, and completed questionnaires at their initial clinic visit and follow-up visits asking them to self-report the number and severity of concussion symptoms on a postconcussion symptom scale (PCSS) which they first experienced at the time of injury and within 24 hours of their clinic visit, previous number of concussions, presence of the loss of consciousness or amnesia at the time of injury, and prior treatment for headaches.

During each follow-up clinic visit, the study participants, the majority of whom sustained their concussions during collision or contact sports, reported their physical activity level, the number and severity of symptoms they were still experiencing, or, if symptom free, the last date on which they experienced symptoms. The data was then analyzed to determine the association between symptom duration, initial clinic visit responses, and self-reported physical activity level and cognitive activity after the injury.

*Ratings on this scale were adapted from the stages described in the graduated return-to-play protocol provided by the 2012 Zurich Consensus Statement on Concussion in Sport.

Of the seven in ten who eventually reported the date on which they became asymptomatic for concussion, the average recovery time was 48.9 days, which did not vary significantly by age. A majority (76%) reported a period of physical rest between the time of injury and initial examination.  Consistent with previous studies, a higher total PCSS score at the initial clinic visit was found to be independently associated with a longer duration of symptoms. A stronger association between female sex and symptom duration was also reported, suggesting that female patients may be at a greater risk for symptom persistence after concussions.  Such finding was consistent with some studies finding that female patients have greater cognitive deficits after concussions than their male counterparts, but not with others, which found no consistent sex bias. Combined with another recent study finding that the the symptoms reported by female patients significantly differed from that of male patients, with female patients reporting more symptoms both at baseline and after a concussion, the findings led Howell and his colleagues to conclude both that initial symptom burden may still be among the best predictors of a prolonged recovery from concussion, female patients may also possess a greater risk for symptom persistence after concussions than male patients.

Study limitations

The study’s authors were quick to point out that there findings needed to be viewed in light of several limitations.  First, the fact that study participants took on average 49 days to recover from their concussions made them atypical from the general population of athletes who sustain concussions whose recoveries are shorter (e.g. 98% of high school athletes report symptom recovery within 28 days of injury and adolescents require approximately 30 days after a concussion to return to similar symptom severities as a matched control group.

Second, objective measures of concussion recovery, such as neurocognitive, balance, and visual function assessments, were not conducted; instead, only self-reported symptom severity, which many health care professionals utilize in making concussion management and return-to-play decisions, was utilized

Third, researchers relied on patients’ recall of self-reported activity level instead of a controlled exercise training program and did not capture cognitive activity. The authors recommended that future prospective trials examining the effects of exercise training on pathophysiology and persistent concussion symptoms employ a standardized exercise program.

Finally, the researchers admitted that data regarding the symptoms and resolution times of prior concussions were not obtained and may have affected their results.

Howell DR, Mannix RC, Quinn B, Taylor JA, Ozan Tan C, Meehan W. Physical Activity Level and Symptom Duration Are Not Associated After Concussion. Am J Sports Med (published online February 2, 2016) DOI: 10.1177/03