Hydrotherapy and Chronic Pain – All You Need To Know

Hydrotherapy can be very useful in treating chronic pain. This article takes you through what you need to know.

What is hydrotherapy?

Hydrotherapy involves the patient being in a heated pool of water, carrying out specific exercises. The water is usually heated at between 33 and 36 degrees Celsius. This is warmer than a typical swimming pool. In some cases, the water may be cooled rather than heated, to treat specific medical conditions.

The concept of using water to treat health conditions is not a new one. There is record of water being used in this manner as far back as the Ancient Egyptians. During that time, royalty would bathe in warm pools of water to relax and promote good health. In the present, hydrotherapy can be used to treat a wide variety of medical conditions including mental health, supporting recovery from surgery, neurological conditions and chronic pain.

Four properties of water

There are four properties of water which contribute to the positive effects gained through hydrotherapy:

  • Buoyancy: This is defined as an “upward force that opposes gravity”. This is what gives us the ability to float when we’re in the water, and what makes us feel less weighed down than on land.
  • Hydrostatic pressure: This is simply the pressure that the water puts on the objects within it.
  • Hydrodynamic drag forces: This is defined as a force which, “acts in an opposite direction to the line of the movement”. So when you walk in water, you experience some resistance.
  • Thermal conduction: Water has the ability to conduct temperature 25 times faster than air. When we’re in water, we can also transfer our body heat into the water, as well as the heat of the water transferring into our bodies.

Let’s take a look at how these four properties can help to treat chronic pain.

How can hydrotherapy treat chronic pain?

Exercise has many health benefits for those with chronic pain, including building general fitness, building muscle strength and reducing stress. However exercise can often be painful or cause a flare. Functioning can be reduced in pain patients and a negative perception of pain can cause patients to avoid activity. This can lead to the body becoming deconditioned (weakened through lack of use) and reduced confidence, among other negative effects. Hydrotherapy can help to reintroduce the patient to exercise and build that strength back up in a safe, pain relieving environment.

The heated water helps to ease pain, allowing you to perform the gentle exercises more comfortably. The exercises performed in the water, like other forms of exercise, cause a release of endorphins. Endorphins are a chemical which promotes a general sense of wellbeing and happiness, as well as acting like the body’s natural pain reliever. They work like opioids, interacting with the opioid receptors in the patient’s nervous system and producing an angelisic affect. However unlike opioids, they don’t cause side effects!

The sensation of being in the heated water is thought to interrupt pain signals and therefore also help to relieve pain. This study explains, Sensory-motor hyperstimulation exerted by the hydrostatic pressure, viscosity, and water temperature increases the triggers of thermal receptors and mechanoreceptors while blocking nociceptors.” This is similar to if you use a heat pad on painful areas to relax your muscles and relieve pain, or if you rub a painful area to produce a different sensation which interrupts pain signals.

Often when patients have been inactive through fear avoidance (fear of worsening symptoms) they can lose confidence and think that they cannot perform certain movements. Doing exercise in the water helps to take the weight off your joints, which makes movement a lot more manageable. Learning how to perform movements in the water can gradually build the patient’s confidence. This can help them to see that they can get out there and be active and that their body is capable of movement. This makes it more likely that patients will engage in exercise in their day to day life.

Carrying out movements in a setting that eases pain also helps to retrain the brain away from pain. The brain is being taught that these movement’s do not need to be feared and that they don’t need to cause pain. In turn, the brain can stop sending messages in reaction to these movements. If the patient continues exercise after hydrotherapy, this positive feedback is continued

For many of us, fatigue is a very debilitating symptom of chronic conditions. This severe lack of energy can make any movement feel like you’re climbing a mountain. When you’re in the water, the buoyancy is taking the weight of your body. This means the movements take less energy and are more manageable, even for those who struggle with severe fatigue as explained in this study

While carrying out exercises in the water can take the weight of the joints, it also helps to provide a safe amount of resistance during movements. This helps to really build muscle strength and get the body fit once again. The deconditioning we mentioned earlier can contribute to pain and make it hard to engage in activity. By strengthening the muscles, hydrotherapy is reducing pain and preparing the body for regular movement. The exercises also help to reduce inflammation and improve the patient’s balance as this study concluded. 

The warmth of the water increases circulation, which promotes better healing within the body, improves your immune system and helps your body provide oxygen to your organs. This helps your organs to function effectively and gives you the energy you need to function.

During the hydrotherapy session the warmth and the calming setting can often promote relaxation. Hydrotherapy should be a positive experience for the patient. It’s been proven that during hydrotherapy, levels of stress hormones (such as cortisol and norepinephrine) are reduced. Reducing stress can in turn reduce pain levels.

The reduction of these stress hormones can also improve sleep within patients. Insomnia is often something which chronic pain patients struggle with. Lack of sleep can perpetuate chronic pain symptoms as well as having a negative effect on general health. Improving a patient’s ability to sleep restfully can have a considerable positive impact on quality of life.

This study on how patients with fibromyalgia could benefit from hydrotherapy found that they were significantly improved in the following areas after the treatment: “physical function, work absenteeism, ability to do job, pain intensity, fatigue, morning tiredness, stiffness, anxiety, and depression.”

When hydrotherapy is combined with other treatments such as pain neuroscience education and psychological therapies, it can produce more long lasting results as this study concludes. This multidisciplinary approach can equipt patients with the tools they need to manage their pain more effectively, and most importantly, to continue benefiting from their treatments in the long term.

What to expect during a hydrotherapy session

A hydrotherapy session may be done individually or in a group setting depending on the needs of the patient. You may be referred to a hydrotherapy pool within a specific clinic or hospital setting. Some spas and swimming pool facilities may have hydrotherapy facilities. Often hydrotherapy is offered as part of physiotherapy or within a pain clinic setting. In a clinical setting, hydrotherapy is carried out by a physiotherapist as standard. You can also access hydrotherapy privately. If you do choose to pursue hydrotherapy privately, ensure that the therapist and the facility are appropriately registered.

Take any medications you will need while you’re there, for example painkillers. You’ll need a swimming costume and a towel. When you get there, the therapist will have your medical records but will still chat to you before the session about your health issues and what your goals are from the sessions. They’ll explain your treatment plan and what type of exercises you will be engaging in.

It’s natural to be a little nervous, especially if you’ve been doing very little movement or activity. Try to remember that the therapist is a person like you or me, and they are used to working with people in your situation. Talk to them and express any concerns you may have. Hydrotherapy sessions are usually around 30 minutes long. You will usually attend once a week for five or six weeks.

Once you’re ready to get started with your sessions, you’ll go to a changing area and get into your swimming costume. You’ll then meet the therapist at the pool. You don’t need to be able to know how to swim or be confident in the water. The pool will typically be waist or chest height throughout, so you’ll always be able to stand in the water. Usually the therapist will be joined by an assistant to help guide you, especially if it’s in a group setting, so that everyone can get the help they need.

The therapist or assistant will then guide you into the water. This may involve walking down steps into the pool, or if you are struggling they may use a medical hoist to lower you into the water. You may use floats once you’re in the pool to support you. There will be a rail around the pool to hold onto if you need it. Depending on your needs, the therapist may guide you from the side of the pool, or they may get into the pool with you.

If the therapist is in the pool with you, they may manually help you to carry out your exercises. If they’re on the side of the pool, they will instruct you clearly step by step. You will first warm up which may be some light stretching, or walking slowly around the pool. You’ll then get started on the exercises which are tailored to your needs. They will typically be slow, gradual movements and stretches. For example, you may balance on one leg, do arm stretches or gentle lunges. As the sessions progress, you may start to do slightly more strenuous exercises, such as walking faster or jogging in the water. It’s completely natural to feel a little tired afterwards, just like with any other exercise.

At the end of the course of sessions you should have an increased sense of confidence about moving your body and a better idea of what your body can do. The aim is to increase your levels of functioning and quality of life going forward. Once you’re finished the sessions, your therapist may ask you to continue carrying out exercises at your local pool. They may even encourage you to go swimming (or learn to swim if you need to). Swimming can build on the work of hydrotherapy, allowing you to do regular exercise while still having the benefits of the weight being taken off your joints.


  • Mozhdeh Bahadorfar, (2014), “A Study of Hydrotherapy and Its Health Benefits”. International Journal of Research (IJR) Vol-1, Issue-8

  • Zamunér, A. R., Andrade, C. P., Arca, E. A., & Avila, M. A. (2019). “Impact of water therapy on pain management in patients with fibromyalgia: current perspectives.” Journal of pain research, 12, 1971–2007. 

  • Jenny Geytenbeek, (2002), “Evidence for Effective Hydrotherapy”. Physiotherapy Volume 88, Issue 9, Pages 514-529

  • Kyara Morgana Oliveira Moura Silva, Silvia Jurema Pereira Tucano, Claudia Kümpel, et al, (2012), “Effect of hydrotherapy on quality of life, functional capacity and sleep quality in patients with fibromyalgia”. Rev Bras Reumatol 2012;52(6):846-857

  • Versus Arthritis, (2020), “Hydrotherapy”.


Please note: This article is made available for educational purposes only, not to provide personal medical advice.

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