Your question: I think the hot water makes your blood rush to your lower body and you don't have enough blood going to your head. That would make you very tired and dizzy.
Answer: What may happen is that Heat may Cause the Nitrogen Isotope to convert to the Acidic Isotope , thus Causing the Proteins in the body to become Acidic, thus Causing one to have these problems you are mentioning ?
For the Brain needs Oxygen and Natural Sugars for it to work properly, which both of these may become into Short supply when the body becomes too Acidic !
The Heat is what may Cause the Release of the Acids in the body and the Cold shower afterwards may Cause the Nitrogen Isotope to convert back to an Alkaline Isotope !
But, if one is Lacking in the needed Alkaline Mineral Reserves in their body, then one may have a problem of overloading their Lymphatic Fluids with too much Excess Acids, if using the wrong ingredients in the Detox Bath and if trying to remove too much Acids too Fast ?
If one runs into problems with the detox bath, then one may need to just use the Peroxide and some Epsom Salt to start with and nothing else ?
AS Always, the more Sick a person may be, the Slower one needs to try to Correct the problems, so as to not overload their Lymphatic Fluids !
As usual not everything may be as it may first seem to be !