Skip links


What is Hydrotherapy?

Hydrotherapy is any activity, exercise or therapy performed in water to assist in rehabilitation and recovery. Hydrotherapy has been used for thousands of years, with evidence dating back as far as the Roman Civilization. Hydrotherapy uses the physical properties of water to improve the outcome of the rehabilitation process. These properties include buoyancy, resistance to movement, turbulence and instability, and temperature.


Buoyancy is related to the density of an object floating in water. The denser an object, the more likely it is to sink. This property creates a change in weight bearing forces, decreases muscle spasm and guarding, reduces pain and helps with the development of pre-functional activities. The changes in weight bearing forces means that essentially the deeper you are in water, the less weight you have to take. These numbers will vary slightly depending on the individual, but when you are hip-height deep in water, you are taking 50% of your own body weight, at your lower sternum you are taking 30% and in neck deep water, you are taking 10% of your body weight. When you are taking less weight at different depths of water, this allows you to strengthen and practice movement much more easily, and as you progress your therapist can take you into shallower water, and eventually on land (where you are taking 100% of your body weight) (Edlich et al., 1987).


Resistance is to movement is created through frontal resistance, skin drag and turbulent drag. It is this resistance that allows for muscle strengthening and dampens down unwanted movements such as dyskinesia. Turbulent drag is created when water is displaced by movement and creates a negative pressure behind the person or object. Skin drag is also 790 times greater in water than on land, which makes your body work harder to move through it and hence improves muscular strength (Edlich et al., 1987).


The temperature of a hydrotherapy pool aims to be around 34 degrees Celcius. This temperature is considered ‘thermoneutral’ which means that your core temperature is not affected. This why you can spend a lot of time in a hydrotherapy pool and not feel any hotter or colder. Colder temperatures are shown to increase muscle tension and spasm and hence are not appropriate for rehabilitation purposes.

Effects of Hydrotherapy

Hydrotherapy affects many body systems including cardiovascular, respiratory, renal, temperature regulation and sensory and psychological.


- Increases central blood volume
- Increases cardiac output by 30%
- Increases stroke volume by 50%


- Causes hydrostatic pressure on trunk
- Increases work of breathing
- Increases airways resistance


- Increases sodium, potassium and calcium excretion

Temperature Regulation

- Hydrotherapy pools should sit around 34 degrees Celsius which is a thermoneutral temperature
- Core temperature is not affected during normal hydrotherapy sessions at thermoneutral temperatures
- Cold pools can increase muscle spasm

Altered Sensory Input

- Reduces joint position sense input
- Increases tactile input
- Increases vestibular stimulation


- Decreased fear of falling
- Relaxation
- Learn to move easily and without pain (Mooventhan and Nivethitha, 2014)

Who can it benefit?

Hydrotherapy can be used for a variety of conditions and throughout various life stages. These include but are not limited to:

- Cerebral palsy
- Stroke
- Acquired Brain Injury
- Multiple Sclerosis
- Motor Neuron Disease
- Spinal Cord Injury
- Joint replacements
- Sporting Injuries
- Arthritis

Speak to one of our physio to see if hydrotherapy is the right fit for you or your child!


Edlich, R., Towler, M., Goitz, R., Wilder, R., Buschbacher, L., Morgan, R. and Thacker, J., 1987. Bioengineering Principles of Hydrotherapy. Journal of Burn Care & Rehabilitation, 8(6), pp.579-584. Mooventhan, A. and Nivethitha, L., 2014. Scientific evidence-based effects of hydrotherapy on various systems of the body. North American Journal of Medical Sciences, 6(5), p.199.

Leave a comment