Mild aerobic exercise significantly shortened recovery time from sports-related concussion in adolescent athletes, compared with a stretching program in a randomized trial of 103 participants.

Feet on a treadmill YanLev/ThinkStock

Sports-related concussion (SRC) remains a major public health problem with no effective treatment, wrote John J. Leddy, MD, of the State University of New York at Buffalo, and his colleagues.

Exercise tolerance after SRC has not been well studied. However, given the demonstrated benefits of aerobic exercise training on autonomic nervous system regulation, cerebral blood flow regulation, cardiovascular physiology, and brain neuroplasticity, the researchers hypothesized that exercise at a level that does not exacerbate symptoms might facilitate recovery in concussion patients.

In a study published in JAMA Pediatrics, the researchers randomized 103 adolescent athletes aged 13-18 years to a program of subsymptom aerobic exercise or a placebo stretching program. The participants were enrolled in the study within 10 days of an SRC, and were followed for 30 days or until recovery.

Athletes in the aerobic exercise group recovered in a median of 13 days, compared with 17 days for those in the stretching group (P = .009). Recovery was defined as “symptom resolution to normal,” based on normal physical and neurological examinations, “further confirmed by demonstration of the ability to exercise to exhaustion without exacerbation of symptoms” according to the Buffalo Concussion Treadmill Test, the researchers wrote.

No demographic differences or difference in previous concussions, time from injury until treatment, initial symptom severity score, initial exercise treadmill test, or physical exam were noted between the groups.

The average age of the participants was 15 years, 47% were female. The athletes performed the aerobic exercise or stretching programs approximately 20 minutes per day, and reported their daily symptoms and compliance via a website. The aerobic exercise consisted of walking or jogging on a treadmill or outdoors, or riding a stationary bike while wearing a heart rate monitor to maintain a target heart rate. The target heart rate was calculated as 80% of the heart rate at symptom exacerbation during the Buffalo Concussion Treadmill Test at each participant’s initial visit.

No adverse events related to the exercise intervention were reported, which supports the safety of subsymptom threshhold exercise, in the study population, Dr. Leddy and his associates noted.

The researchers also found lower rates of persistent symptoms at 1 month in the exercise group, compared with the stretching group (two participants vs. seven participants), but this difference was not statistically significant.

The study findings were limited by several factors, including the unblinded design and failure to address the mechanism of action for the effects of exercise. In addition, the results are not generalizable to younger children or other demographic groups, including those with concussions from causes other than sports and adults with heart conditions, the researchers noted.

However, “the results of this study should give clinicians confidence that moderate levels of physical activity, including prescribed subsymptom threshold aerobic exercise, after the first 48 hours following SRC can safely and significantly speed recovery,” Dr. Leddy and his associates concluded.

The study was supported by grants from the National Institutes of Health. The researchers had no financial conflicts to disclose.

SOURCE: Leddy JJ et al. JAMA Pediatr. 2019 Feb 4. doi: 10.1001/jamapediatrics.2018.4397.