Concussion is a subject of interest which has gained a lot of attention over the years, and this has been due to a 15-fold increase in mild traumatic brain injury. The past approach for concussion management was enforced rest, both physically and cognitively, until symptoms resolved. This method wasn't actually backed up by scientific evidence, but the reasoning behind it was to limit exposure to environments that might lead to secondary concussions. So, the notion of avoiding secondary injury was prioritised over proactive recovery.
More recently, research studies have indicated that sub-maximal aerobic exercise is more effective in managing concussion symptoms. Low-to-moderate intensity aerobic exercise has shown to have a positive influence at various levels of brain function, including somatic, cognitive, emotional and sleep-related systems.
After 24-48 hours post injury, it is advised the patient walk on a treadmill with the incline gradually increased, or cycle on a stationary bicycle against progressive increasing resistance, all under supervision. Aerobic exercise is thought to have an influence on the autonomic nervous system which is disturbed following concussion. Sub-maximal aerobic exercise normalises cerebrovascular physiological dysfunction, which in turn reduces arterial carbon dioxide. High levels of arterial carbon dioxide increased cerebral blood flow out of proportion to exercise intensity, creating exercise intolerance. Modulating the autonomic nervous system helps to accelerate recovery, and reduce the likelihood of developing persistent post-concussive symptoms.
Leddy, J.J. et al.,(2019). Exercise is Medicine for Concussion. Curr Sports Med Rep. 17(8). 262-270.