Medium-Intensity Stimulus: Seat or middle body baths at cold temperature, upward, hot or contrast ones, steam baths, sauna and whole body covering with a medium length.

High-Intensity Stimulus: Hyper-thermal bath, steam bath, intestinal bath, whole body long length damp covering and pressure cold or very hot jets.

Reactions our organism to hydrotherapeutic applications at different temperatures are:

At vascular level

- First stage: Paleness, gooseflesh, cold sensation, which produces pain.
- Second stage: Skin reddening, heat sensation and well-being.

- Only one stage: Heat sensation, skin reddening and general well-being.

- First stage: Paleness, gooseflesh, pressure sensation and pain.
- Second stage: Skin reddening, much heat sensation that decreased to a nice well-being sensation.

At cardiorespiratory system level, cold water decreases heart activity and frequency and increase blood pressure, producing a vasoconstriction. Hot water produces an increase of heart frequency and a decrease of blood pressure because of a vasodilatation. Depending on the kind of application, complete baths increase vein pressure, increasing blood quantity.

At respiratory system level, sudden cold or hot applications produce a deep and lasting inspiration. Cold water long length applications produce a deep and fast respiration. Long length hot water applications produce deep respiration but more superficial.

In respiratory pathology, the most helpful thing to respiratory reeducation, one of the first stages in any respiratory treatment, is got with complete baths that make respiratory movements easier and make difficult the inspiration ones.

At hematology level cold water applications increase red blood cells, blood viscosity and concentration and hot water applications make haemoglobin and leukocytes level decrease.

In muscular skeleton system, cold water applications produce muscular hyper-tone and increases nervous excitability improving the capacity of muscular work. Long length hot water baths produce muscular hypo-tone and decrease of muscular excitability which takes to muscle relax. Cold or hot baths decrease pain perception.

On nervous system, cold water applications act on the sympathetic nervous system. Hot water applications act on parasympathetic nervous system and hot water applications on both of them.

At At organic working level in entrails or other organs, hot water applications increase intestinal motility and stomach function, stimulating biliary secretion, improving kidney function and, with it, increases diuresis. Cold water applications decrease intestinal motility of the digestive tract and stimulate biliar secretion as well as the hot ones. In short length applications (feet, seating and middle body baths) stimulate urinary bladder emptying.

External hot applications applications relax muscular fibbers, decreasing colic and constipation. Cold applications, both internal and external, are indicated in case of lazy intestine, atony or womb flaccidity with strong haemorrhages, vascular atony, etc...

Hydrotherapy, at general level, and depending on the sort of application, is going to produce with short length cold or very hot applications, a stimulating and refreshing action. With tepid or indifferent temperature baths a sedative effect and becoming of sleep is produced, with long length very hot baths a restlessness sensation and insomniac is got, particularly if they are taken in the evening.