https://my.clevelandclinic.org/health/diseases/9385-low-blood-pressure-orthostatic-hypotension
Orthostatic hypotension. Low blood pressure from standing up too quickly.
I got this from time to time, especially when first starting fasting. Just really have to focus on moving slower, until your body re-adjusts to the lower blood pressure.
(It’s amazing that doctors treat high blood pressure with meds, when abstaining from eating (carbs in particular) will drop blood pressure significantly more than meds.)
It’s suggested with water fasting and dry fasting that we should stand up slowly due to reduced blood pressure. To relay a personal experience, I had to over-exert myself in the summer Florida heat and sun and I did feel like I was going to pass out. I had to lie down for awhile and cool down. So I advise listening closely to your body during any fast. Fasting is different person to person. Also individually, each fast is different.