I have to agree that getting hot is a trigger for many, I think that a sow stretching form of yoga would be ok. We all want to maintain some feeling of control with this mess and that could help you do that.
I hope that you have a mouth guard for your bruxism! I would not think that all the grinding would be a good thing. As in you don't want to aggravate any of the Trigeminal Nerves. My mouth guard has to be replaced fairly often.
O2 should be your best friend!! You need to have 15 to 25plm and a non-rebreather mask. 100% O2, not a concentrator. You don't mention a doctor, so do you have one who could prescribe the O2 for you? Have you had a scan to rule out any abnormalities upstairs that could be an issue? Usually that scan is a MRI. And are you on any preventatives?
While I have not heard of heat 'triggering' a cycle, a negative response to getting hot can be the signal that a cycle has begun. Sort of like having a beer and getting hit right away. The beer signaled the beginning and is a trigger in cycle.I have had several cycles announce their presence by getting 'triggered' by something that I had no problem with the day before. It can certainly trigger a hit when in cycle!
And, just when we think that we 'know' the beast, it can change. Pretty sneaky it is.