Should you exercise after a concussion?
The traditional recommendation for post-concussion recovery has been a restriction of physical and cognitive activity for a certain period of time or until symptoms resolve. However, research suggests that prolonged rest beyond the first couple of days after a concussion can hinder rather than promote the recovery process.
Concussion affects the autonomic nervous system and its control of cerebral blood flow CO2 level sensitivity and cardiac rhythm. The primary autonomic control center is located in the brain stem and is implicated in traumatic brain injury especially if any rotational force in the neck occurred with the trauma event. Uncontrolled activity can exacerbate symptoms after a concussion due to these alterations in CO2 sensitivity and cerebral blood flow and this is why rest rather than activity has traditionally been encouraged so as not to exacerbate symptoms.
However, research has found that sub-threshold aerobic activity or activity to a level that does not trigger post-concussive symptoms can improve exercise tolerance, reestablish normal CO2 sensitivity and promote recovery. For example, an interesting study involving female athletes with a post-concussive syndrome that had abnormal CO2 sensitivity due to concussion displayed relative hypoventilation during exercise that raised CO2 levels out of proportion to exercise intensity. This response raised exercise cerebral blood flow disproportionately to the intensity and was associated with symptoms of headache and dizziness that limited their exercise tolerance to low levels. A program of sub-threshold aerobic exercise treatment restored their CO2 sensitivity to normal and improved their exercise tolerance.
Excerpt from Dr. Chanel’s paper ‘Concussions – Pathophysiology and Nutrition for Recovery’
References:
Signoretti, S., Lazzarino, G., Tavazzi, B., Vagnozzi, R. (2011), The Pathophysiology of Concussion. PM.R. 3(10):359-369. DOI: 10.1016/j.pmrj.2011.07.018
Leddy, J., Hinds, A., Sirica, D., Willer, B. (2016). The Role of Controlled Exercise in Concussion Management. PM&R. 8(3):91-100. doi.org/10.1016/j.pmrj.2015.10.017