For safety's sake I will add this here too so people can see it.
I just measured my blood potassium levels 6 days after the fast. They we're dangerously low (3.2) and I am lucky to be here now.
Please avoid sauna during your fast and read your body signs carefully! Especially abnormally high resting pulse (100-120) combined with low-bp-like symptoms can mean a serious deficiency of electrolytes in your body, which can read to heart rhythm problems or even death.