Mineral waters mechanisms of action

When a visitor-bather comes in contact with the spring water at the spa centers, the mechanisms that are activated and contribute to treatment are:

Μechanical Αction

In a group or individual baths, the body receives the impact of two mechanical factors, buoyancy and hydrostatic pressure. The buoyancy causes decrease in body weight and therefore relaxation occurs. At the same time ease of joint movement is generated and the pressure is distributed evenly throughout the body. 
The mechanical stimulus may be in different forms eg hydro-massage, kneading, rubbing, etc. 
The mechanical factor causes changes in the body, such as changes in blood flow, and thus affects the mechanism of thermoregulation.

Thermal action

The thermal stimulus occurs when the water temperature is above or below the skin temperature. 
The thermal environment of the bath has different properties from those of the atmospheric environment. 
The body thermoregulation in the bath is different than in the air. The temperature lead to an increase in energy, and activates thermoregulating mechanisms dilates surface blood vessels enough and increases the perfusion of the skin resulting in better skin blood flow. The temperature increase of the muscle results in easier and stronger contraction of them. As the pain is alleviated the bather can move with greater ease and increase the range of motion of stiff joints.

Chemical action

The chemical stimulus is created when the dissolved components of the metal-spring water get on the skin of the bather or penetrate inside the skin, where they exert their pharmacodynamic action. 
The rate of entry into the skin depends on their concentration in the water, the water’s pH, the length of the bath, the temperature, the condition of the skin and the whole body. The various substances prefer to be stored in specific organs of the body eg iodine in the thyroid, the bromine in some parts of the brain, the iron in the red blood cells, the carbon dioxide in the liver, etc. 
During the bathing physicists, physical, chemical and mechanical agents are engaging some form of body reflex physiotherapeutic treatment, with the ultimate goal being to achieve the final therapeutic effect. 

10+1 Useful tips for a proper hydrotherapy!

You must strictly follow treatment instructions, given to you by your doctor after medical examination.
Any reaction occurring during hydrotherapy should be reported to the physician of the Baths.
Bathing should be done with an empty stomach or after digestion, three hours after the last meal or a hearty breakfast. Hydrotherapy should not be extended beyond the given period, because it acts against your body.
During the thermal treatment and for a few days after the end of it avoid washing the thin layer of metal salts deposited on the skin.
Do only the necessary hygiene.
Get exposed to the sun for a short time only during morning and evening hours.
During hydrotherapy (baths-inhalation) temperature fluctuations should be avoided.
• For this reason, we must not leave the spa premises before the appropriate time the body needs to adjust, which is at least 30 minutes.
• During menstruation, spa treatment should be discontinued.
• Hydrotherapy which usually takes 15 days must be interrupted for a couple of days.
• Often during hydrotherapy, you may experience the symptoms of your illness more vigorously. It is the body’s reaction and you should not worry. If the symptoms are very severe and accompanied by other general symptoms (hydrotherapy relapse), ask the spa’s doctor.
• Bear in mind that a hydrotherapy relapse eliminates itself, without consequences, with a brief interruption of hydrotherapy.
• During hydrotherapy you should follow proper diet, focusing on fresh foods. Avoid spicy foods, alcohol, coffee, etc.
• A principle of good health is to spread as much of your free time in the spa, when possible, with appropriate rest and exercise (walks in open parks, gymnastics etc.), so that you achieve a healthy natural stay in the Loutropolis.

"Developed" versus "wild" hot springs, and what's a spa?

The term "hot spring" means different things to different people, and it's a good idea to know just what manner of hot spring you're bound for at a destination, because it may be something quite different from what you're expecting. In English the term is used more or less interchangeably for "wild" springs, where the water emerges directly from the ground into a natural catchment that can be used for bathing, and "developed" springs, which exploit the spring through construction of man-made artifacts such as pools and bath houses. "Wild" springs and "developed" springs can differ so much, and in so many ways, that the visitor expecting one and getting the other may not enjoy the experience very much. 
Some examples:

Wild springs are often (although not always) on public land or otherwise accessible to the public without charge, while developed springs are almost invariably intended by the developer to make a profit, and hence will charge (and be in a legal position to demand) an admission fee.

You can't count on creature comforts at a wild spring; you may have to sit on a rock at water's edge to doff your clothing, and pre-entry showers are pretty well out of the question, let alone amenities like poolside drinks that a developed spring may offer. On the other hand, wild springs are generally open-air and take you "back to nature" in ways that a developed spring may not.

At a wild spring, water temperature is purely on an as-is basis; the pool where you bathe will be at a temperature that's regulated solely by the relative proportions of water from the spring and meteoric (surface) water that the terrain imposes. As a consequence, water at wild springs can be uncomfortably, or even dangerously, hot. Commercial operators of developed springs will generally ensure that the water temperature is appropriate (sometimes offering several choices of temperature in different pools) through dilution of the spring's effluent with water from the commercial supply or other sources. This distinction is particularly important; the bather used to "tame" water from a commercial spring who wades directly into a seething-hot wild spring can receive a painful, or even fatal, surprise.

Hot-spring water is usually fairly safe from the standpoint of carrying disease-causing organisms, but some is not (see below under "Stay healthy"), and the surface water that cools a scalding spring to usable temperatures will be prone to the same bugs and pathogens as any other surface water. Operators of developed springs may (or may not) take steps to disinfect the water, but at a wild spring, you're obviously on your own.

Note, incidentally, that a "developed" hot spring is not necessarily a commercial hot spring, i.e., one that has been developed for profit-making purposes. The distinction can be important in countries and regions where the political/economic system allows for both for-profit and public-interest/non-profit/governmental development; regulations for doing the developing will often differ between the two cases, as will the resulting amenities, access, etc. For example, as a general rule, springs in the United States that have been developed by government will have fewer amenities, but also lower admission fees, than for-profit developments. In Japan, many hot springs in rural locations are maintained by the local government and are open to the public for free, and even expensive spa resort towns usually have at least one public bath open to all for a token fee.

Spas

There is a difference between a hot spring and a spa. The latter term denotes either a pleasantly warm tub of water (not necessarily originating in a hot spring) suitable for bathing for medicinal and recreational purposes, or the -- sometimes incredibly elaborate, luxurious, and expensive -- resorts where such tubs can be found, which incorporate massage, body wraps, and so on. Not every spa is based on a hot spring (many, perhaps most, simply heat meteoric water to the desired temperature); not every developed hot spring has spa-like amenities.