powerful pins and needles vibrating feeling in my head, chest and arms

Hello,

I recently started back to hot yoga after a 2 year gap. Before I stopped I had been going every day for several months. I have been going 5-6 times a week for 3 weeks now and occasionally get hit with a very powerful feeling similar to pins and needles / vibration in my head, chest and arms.

It starts very subtlety in my fingers and then slowly spreads up my arms, into my head and across my chest. The sensations causes my muscles to tense up on their own, and no matter how hard I try to relax nothing helps until class ends I am able to leave the room and chill out away from the heat/drink a whole bottle of water. This feeling doesn’t always hit me, but when it does (like today) it can lay me out for the whole second half of the class. Focussed, calm deep breathing does not seem to help.

I notice it hits me more often when I go to the morning sessions, which makes me think maybe it’s lack of water or food (I wake less than 3 hours before my class, so wait to eat until after class). I drink a couple of big glasses of water in the morning as soon as I wake up.

Is there anything you can suggest that I can do to stop this feeling from coming back? I love hot yoga and really want to be able to get the full benefit from all the postures every time I go.

Thank you!
Anna