Hello!

I highly recommend looking into to Buffalo protocol where you monitor your heart rate as you return to exercise. After my injury in March 2018 I was unable to walk more than a block without a spike of symptoms.

After 4 months I got a heart rate monitor and began monitoring. At first I could walk for 20 minutes at 120BPM. this was VERY frustrating as I was walking so slowly (less than 1km in 20 min). But over the months I have increased. Everytime I found that I feel no increase of symptoms I would increase my heart rate threshold. For to 125bpm then to 130bpm and so on.
When I got to 140bpm I also started to increase the time that I could workout. They recommend for this protocol you either walk or use a stationary bike at first as it's a consistent way to keep in control of your heart rate. And this doesn't move your head a lot so you don't get vision symptoms. Also during this time if your symptoms spike rapidly more than 2 pain points (so for example you headache goes from a 4/10 to a 6/10) stop and try again another time maybe at a lower heart rate.

Now (11 months on) i am able to life light weights for 1 hour with a heart rate max of 150. Somedays I still have symptoms after exercise, but if I don't push it I generally don't. Weights are less predictable heart rate rise, however because I was an athlete before my injury I find the emotionally boost I get from weight lifting is worth a small setback for the next day.

The theory behind this protocol as I understand it is that after a tbi when you work out the increase of blood to your brain is seen as a threat and your brain doesn't know how to deal so it increases symptoms to protect itself. Slowly retraining it that exercise is safe in this gradual method helps it realize exercise is not a threat.

I really hope this helps you, it's the only method that has helped overcome my exercise intolerance. It's a long, but worthwhile, process.