Yes,

I've experienced exercise intolerance and it dramatically lessens overtime, especially after 1-2 weeks in my experience and from what I know after reading other peoples story. Not every concussion is the same. Try to go for steady state low impact cardio like on the treadmill or stationary bike, start with 20 min moderate-level exercise that includes both warm-up for 5 min and a cool-down for 5 min, and active exercise for 10 minutes. Do this 4-5 times a week and then add another 5 minutes to that every week if you are able to.