My friend who has had 5 concussions (2 severe) had symptoms for 6 months after his worst concussion. He was cross-checked with a lax stick. His symptoms were so bad at first that he struggled to plan activities for his day, as his memory was that poor. He had daily migraines, light sensitivity, etc...In about a month of exercise, his symptoms went away. He said that the first week or two he had terrible headaches after exercising, but he kept doing it anyway and the symptoms subsided.

He is now top of his class as at the University of Colorado, with a booming social life and excellent cognitive abilities. I am not saying this is a miracle cure, but exercise is important for our physiology. Many symptoms of concussion are often similar to symptoms of stress, which is worsened by lack of exercise. Nothing is more depressing than having no physical activity in your life...and nothing is worse for headaches than sleeping too much. I am not saying run a mile, but I think at least walking could be beneficial for a lot of us. Walking surely should not worsen your symptoms.