Aerobic exercise soon after a sport-related concussion can speed recovery in adolescent athletes, a randomized trial suggests.

“This is not saying that they’re ready to go back to sport yet, it’s trying to treat the concussion so they recover faster in a safe way and get them to the point where they can” start playing again, Dr John Leddy of the State University of New York at Buffalo, the study’s lead author, said in a telephone interview.

Until recently, he noted, guidelines had recommended complete physical and cognitive rest after concussion, but there is growing evidence that low-level physical and mental activity is not harmful and may be beneficial.

After systematic determination of treadmill exercise tolerance, Dr Leddy and his colleagues randomly assigned 103 male and female athletes, aged 13 to 18, to start an aerobic exercise program or a placebo stretching regimen that did not increase heart rate. The mean time from injury to first evaluation was five days.