Have any of you who can't do strenuous excercise without symptoms worsening found any workarounds or low impact exercise that can get the heart rate up without having a negative effect on your head?

I think exercise bikes and other low impact gym equipment might be the way forward, I've never tried these things because I pretty much ruled out any sort of exercise other than walking.

I guess this all depends on if the issue is movement, heart rate or a combination. I'd like to find out but am a bit cautious.

Anyone have any advice or experiences to share?