Water is so ubiquitous that we rarely think about it, much less consider it as a tool in the treatment of disease and the maintenance of health. However, water has been used as a therapeutic agent by healers throughout the ages – the Egyptian, Assyrian, Persian, Greek, Hebrew, Hindu and Chinese civilisations all left records of this.

Water has some very special properties which make it ideally suited as a healing agent:

  • Dissolves very many other substances – in fact it is often referred to as a universal solvent. This means that it can be used as a carrier for both delivering therapeutic compounds to the body (e.g. herbal extracts in medicinal baths or fomentations, minerals in medicinal baths, essential oils in steam inhalations) as well as removing or diluting unwanted things from the body (e.g. sinus irrigation, colonics).
  • Is non-toxic and non-irritating, meaning it can be used internally as well as externally.
  • Comprises about 70% of our bodies and our bodies have about the same density as water, making us naturally buoyant in water. This means we can do exercise while immersed in water so that our bodies are supported by it, making it very gentle and low-impact.
  • Exerts uniform pressure on objects immersed in it. This can be used therapeutically in a number of ways, e.g. in relieving conditions like fluid retention.
  • Has a very high specific heat, which means it is able to absorb or release large amounts of energy without changing its temperature significantly. This allows hot water to efficiently heat things and cold water to efficiently cool things. We can use water in a targeted way to cool or heat a specific part of the body (such as an ice pack or a hot-water bottle), or more generally to cool or heat the entire body (as in a sauna or a bathtub).
  • Inexpensive and universally accessible. Hydrotherapy is easy to use and remarkably safe, making it an ideal modality for home use.
  • Is therapeutically useful in all three phases – solid, liquid and gas – each with its own set of applications.
  • Conforms to the contours of the body – be it in a bathtub, absorbed into a towel, or in the form of steam, as in a sauna.

Naturopaths use hydrotherapy techniques to modulate the flow of blood and lymph in the body. Through our circulatory system, every cell in our body is connected to every other cell. The blood and lymph move nutrients and wastes around in our body as well as various messaging molecules like hormones. Our immune cells and antibodies are also transported through the circulatory system. Thus, having the ability to adjust blood and lymph flow locally and generally is a very useful tool to have.

Heating or cooling a tissue locally will have varying effects depending on the duration and temperature of the application. Generally, cooling a tissue contracts it and heating a tissue relaxes it. A short cold application (up to about a minute) will initially contract tissues (including blood vessels), but this then stimulates circulation as the body tries to heat the cooled area. However, a long cold application (more than a minute) overcomes the body’s ability to compensate and will lead to depressed circulation and metabolism. A short hot application (up to about 5 minutes) relaxes tissues and increases blood flow to an area as blood vessels are dilated. However, a long hot application (more than 5 minutes) will congest the area with static blood, which is not helpful. Alternating heating and cooling applications has a pumplike action as tissues contract and relax repeatedly which improves removal of wastes, nutrient delivery, oxygenation and vitality in general.

In addition to modulating circulation locally and superficially, naturopaths exploit reflex actions in the body to alter circulation at distant sites. Examples of these reflexes are the following:

  • Skin on the hands and feet is reflexively connected with the circulation of the head chest and pelvic regions (including the bladder and reproductive organs).
  • Skin of the breast bone is reflexively connected with the circulation of the kidneys.
  • Skin of the face is reflexively connected with the blood vessels of the head.
  • Skin at the nape of the neck is reflexively connected with the mucous membranes of the sinuses.
  • Skin of the thighs, buttocks and lower back is reflexively connected to the genitourinary organs.
  • Skin of the lower inner thighs is reflexively connected with the prostate in men and the uterus in women.

Using these reflexive connections, the blood flow to various organs and tissues can be stimulated to promote healing and relaxation, or depressed to improve congested conditions – all by heating or cooling distal areas of skin.

Other than the heating or cooling effect of water, various therapeutic agents can be added to water and efficiently delivered to the body through the skin or mucous membranes. This includes fomentations (heating or cooling medicated compresses), medicinal baths with mineral salts (magnesium sulphate, magnesium chloride, sodium bicarbonate, etc.), essential oils, herbal extracts, clays or peat added to the water, steam inhalations with added essential oils, etc.

A third category of effects that water can have on the body is mechanical. The uniform pressure that water exerts on a body suspended in it has been mentioned previously. Another mechanical effect is when the body is sprayed with jets of water, as in a whirlpool tub or with a handheld shower head. The mechanical impact of the jets of water massages the skin and superficial tissues and promotes circulation and drainage of lymph.

Although hydrotherapy practices are very safe and appropriate for home use in most circumstances, they can cause fluctuations in the load on the heart, blood pressure, blood sugar and body temperature and as such, medical supervision is recommended in situations where these fluctuations could be problematic.