Valsalva/hold my breath

[neophyte32]

Good evening,
do you know why holding my breath for 1 minute 30 seconds caused me such a terrible neurological episode? I wanted to test my lung capacity and do some breath-holding (I know, it's stupid) and for the past 72 hours I've had what feels like a concussion, with terrible tinnitus, pain in the top of my head, the back of my head, and my forehead. I had the same thing happen when I did the Valsalva maneuver to clear my ears for the past two years (I was underweight without realizing it).
I had the same sensation when I was running three years ago ; those were my first symptoms, preceding panic attacks during exercise and theb develop MECFS. Does this happen to you too? It's like I have cerebral constriction.

I had a lot of MRIs before being bedridden, and nothing showed up.

 

[Murph]

I have a similar thing. Any hnnngh type activity - like a heavy lift - can cause it. I get that weird pain right on top of my head. Strange feelings near the temple. Takes days to clear.

Among my theories:
Blood flow control failure and ischemia reperfusion injury.

I associate it with POTS. I wonder if the blood flow to the head can fail on both sides, most often too little, but sometimes too much? Just an idea.

(PS, and tell me if you know all this, i'd wager your panic attacks while running are a POTS symptom - pumping adrenaline to constrict blood vessels creates a surge of anxiety)