Orthostatic hypotension. Happens to me when I’m dehydrated and stand up really quickly after laying down. It’s a drop in blood pressure from standing up too quickly, your brain doesn’t get enough oxygen so your bodies response is to get your brain on the same level as your heart, literally. I’ve passed out a few times. When I feel it coming on and try to sit down, or crouch down of I’m not near a chair. I’d try to drink more fluids and be careful standing up quickly. If it persists go get it checked out by a doctor.
Could be heart so get it checked.
Could also be low blood sugar or anemia or something make sure you are getting sufficent nutrients in your eating window.
Why are u doing deadlifts fasted? Do weight training in your eating window and maybe switch to 16/8
Along with what everyone else has said, if you go to a doctor ask if it could be caused by low iron. I used to have issues with iron deficiency and sometimes when I would get up too quickly my vision would go black and I would get dizzy, never actually fainted though.
I’ve had this issue caused by low blood pressure. I also found I wasn’t able to skip breakfast because I’d be dizzy by 10am.
I resolved this (lifelong) issue by adding a quarter teaspoon of salt to a glass of water most mornings. I used to add a little lemon juice to make it more palatable too.
The other comments in this thread are good.
I’d like to add that if you’re on a thiozide for high BP, it acts as a diuretic (causing you to excrete water and salt), and resulting dehydration can cause dizziness when standing up.
It gets worse while fasting, as your insulin level falls and your body holds less water.
So drink and take electrolytes (salt, potassium, and magnesium). Maybe switch BP meds if applicable.