Aerobic exercise may help reduce the symptoms of concussion in post concussive patients, according to a new study. The finding challenges the traditional recommendation of complete rest (both physically and mentally) and suggests that daily low level activity, 10-15 minutes, may diminish prolonged symptoms of concussion.
For the study, “Exercise Intolerance in Individuals With Postconcussion Syndrome”, which was published last fall in the Journal of Athletic Training, researchers at Canisius College recruited 34 concussed males and females, ages 25.9 + 10.9 yrs. On average, the participants had suffered a concussion 226 days earlier.
Postconcussive syndrome (PCS) is a diagnosis that is given when concussion symptoms are still present and not subsiding, at least three weeks after a concussion occurs. According to the World Health Organization PCS includes a history of traumatic brain injury with at least three self reported symptoms. Symptoms of concussion include: headache, fatigue, dizziness, difficulty concentrating, intolerance of stress or light, feeling in a fog, and insomnia.
The study participants were tested by walking on a treadmill. Blood pressure measurements were taken every two minutes and heart rate was recorded every minute. The test ended as soon as any concussion symptoms grew worse. The control group in this study was made up of individuals who had no history of traumatic brain injury. PCS participants were unable to exercise as long as the uninjured control group.
For some time, researchers have known that small amounts of exercise that do not increase symptoms and treadmill testing are safe and effective in the evaluation of concussion in athletes and determining when they can return to sports (Leddy et al. 2010). Clinicians have access to tangible data like heart rate, blood pressure while carefully monitoring concussion symptoms such as headache while patients are on a treadmill, similar to a cardiac stress test evaluation. An asymptomatic response to graded exercise can be and is a key decisive factor for determining return to sport and recovery from concussion.
Noticeably different than its predecessors, the Zurich Guidelines are a stepwise approach that recommends return to play guidelines should progress in 24 hour increments. The athlete should be asymptomatic before advancing to the next level of exertion, if symptoms are exacerbated, the athlete returns to the previous level (Guskiewicz & Valovich McLeod, 2011). The Zurich stepwise return-to-play guidelines are based on consensus and not evidence based studies; they are subjective and vague about intensity and duration.
Cobb & Battin, (2004) suggested that current return to play guidelines may be “too lenient to protect a student from Second Impact Syndrome (SIS)”. Second Impact Syndrome is also called “second impact”, “subsequent head injury”, and “recurrent traumatic brain injury” in the literature. Second Impact Syndrome is a rapid swelling of the brain that can occur hours, days, or weeks after the first brain injury (Cobb & Battin, 2004). Cantu (1996) suggests, “athletes that sustain a concussion are four times more likely to sustain another concussion than those who never had a concussion”. The subject of SIS is currently controversial among researchers but they agree that edema is more likely in the younger brain rather than the more mature brain (Guskiewicz & Valovich McLeod, 2011).
It is agreed that patients must rest mentally and physically during the acute phase of concussion, 1-3 weeks. Beyond three weeks complete rest even “cocooning” may not be the best approach. Karl Kozlowski, PhD, the lead researcher of this study, is developing an individually tailored intervention for athletes to stay in condition, without exacerbating symptoms, while recovering from PCS.
According to researchers, moderate physical activity actually restores the brain’s auto regulation mechanism, which increases blood flow, and simulates neurogenesis in the hippocampus, the memory center, which stimulates the growth of new neurons, or nerve cells. Cerebral auto regulation, the system that maintains cerebral blood flow, may be dysfunctional in people with concussion and may return to normal with controlled exercise.
Regulated exercise allowed for recovery of participants in the study. All but two concussed participants were free of symptoms at follow up. Athletes recovered more quickly (11-36 days) than non athletes (41-112 days). A limitation in this study is the small sample size.
Daily moderate exercise, in a controlled or clinical environment may not only be helpful in the monitoring and recovery from PCS, but a more accurate screening tool for determining return to play. Additionally, controlled graded treadmill testing may be a valuable therapy for depression, cognitive function, neurodegenerative diseases such as Alzheimer’s (Smith et al., 2011), and may help differentiate PCS from other diagnoses such as migraine, post traumatic stress disorder, and depression which share similar symptoms.