What are some symptoms to watch for when starting to increase physical activity including raising heartrate?

I know the Buffalo Protocol has been mentioned as a way to help recover and exercise is healthy in itself regardless of PCS.

I'm trying to snap myself out of this depression because I am really suffering. All input on experience and knowledge when beginning a exercise routine would be appreciated, especially signs and symptoms to watch for to signify overdoing it. I'm starting slow of course.

Soft jogging might be OK, avoid any jarring that might transmit or neck/head of course..

I'd suggest a version of speed walking instead, less risk for tripping or knee,ankle injuries. If you haven't been doing much a good long stroll where you can connect with nature might be the best thing..
Hopefully you can get to a quiet area or a park with trails.. nothing like peaceful nature to sooth the soul..

If exercise does not make things worse, then go for it. If it makes things worse, either you may not be ready to exercise or you're doing too much and need to slow down/do less.

Start small and build up. I don't know where you're at physically, so I'll just say start with a 5 minute walk. If that goes okay for a week or so, try a 10 minute walk. Progress to walking up and down the stairs. This gets the heart rate up very quickly. Then progress to running if your head can tolerate the jostling. If you feel light-headed, get a headache, or get dizzy, take a break. I take breaks during exercise after every set and up to ten minutes sometimes. You may feel fine during exercise and feel really bad afterwards. This is a good sign that you did too much.

Everyone's brain and body are different, but for me, the worse I felt the less I could exercise. Besides walks, it was mostly counterproductive. Now that I'm feeling better, the more I can exercise and the more benefits I get from it.
Also, remember to breathe and not build up tension in the head.

I suggest you follow the Buffalo protocol. Check your heart rate and exercise to increase it 20%. If you have no increase in symptoms at that rate, even delayed increase in symptoms, increase your heart rate after a few days. Step up your target heart rate each week. If you cause an increase in symptoms, back off 10% and see if you can exercise at that heart rate. After a few weeks at that target rate, try increasing your target rate again.

You may find a heart rate that you can maintain for extended periods. That is better than pushing to a symptom level.

I would agree that walking is a better starting point. I worked up to 45 minutes of walking then started running (I had run for 30 years before the accident). Listening to music after two weeks weeks of walk and then audio books.

I started walking twice a day for 45 minutes, no way to be depressed doing that!!!

Danny I had been running for 40 years before I was hurt and wanted to run desperately to
Convince myself of healing.

I ended up being able to walk eventually and have enjoyed it after getting over the embarrassment...my hang up.

I ran last week 2 days in a row for the first time in 22 months. I have found that running on a treadmill with incline eliminates all of the jarring for me, I still can't run on sidewalks but the treadmill has been ok.

For me I have had to proceed very cautiously and build up and determine what was actual judicial symptoms or anxiety induced.

I am excited to hear this from you, good sign!

Bud