I am not an expert on this by any means, but i believe blood pressure loss in a water fast is progressive. 24 hours will not bring your bp down to what it will be in 48, and 48 will not bring it to the 72 hour level. I have to believe at some point it levels off though, perhaps at day 3 or 4. BP getting quite low deep into a water fast is quite normal as it is very much a part of the package. But i am hereby calling out for expert feedback :).