Splish! Splash! Hydrotherapy for chronic back pain is pretty good!

Just a quickie post this morning, but one that I couldn’t resist.
You know how nice it is to be soaking in a hot bath or hot pools after doing some great energetic thing (vacuuming the house? gardening?) – and how many people with chronic pain tell us that a soak in a bath or a hot shower is just great? Well, this study uses a randomised trial looking at traditional exercise or exercise in 33 degree water – and guess what? The exercise in water worked best.

Not too fast there OK, the research design for this study does NOT compare apples with apples. Let’s take a look at some of the problems that I see with the methodology (and why you need to read the research not just cut to the conclusions).

There are a couple of things that help with ‘motivation’ or adherence to treatment – the first is contact with a person who will encourage you, the second is ongoing monitoring, and the third is to have something ‘special’ happening or a ‘special’ place to go to do the treatment. And this study, unfortunately, suffers for not controlling for these variables between the two groups.

The hydrotherapy group got to come in for therapy five times a week, for four weeks, under the supervision of a physiotherapist. And the other group? Given a sheet of exercises, told what to do by the physiotherapist, then left to it. Four weeks later, the results were assessed.

Given our chronic pain population who are often reluctant to move, need a lot of encouragement and supervision, and are probably going to experience an increase in pain especially after the first few exercise sessions, which group do you think did better? Which group do you think actually did the exercise?! I’m prepared to lay money on the group that had supervision, lovely warm water, and had to come in on a regular basis…

A couple of other thoughts occur to me also – when do you think the best time for measuring an outcome might be? Immediately at the conclusion of a treatment or sometime later when the expectancy effects have settled, and the reality of ‘life’ intervenes and the residual effects are what remains? This study measured outcome immediately at the conclusion of the treatment period, so didn’t control for these very influential factors.

I’ll bet that over the next couple of months, there will be a rise in the prescription of hydrotherapy under supervision by a physiotherapist, with this study being cited as a good reason for doing so. I mean, this is a study published in a well-established peer-reviewed and very influential journal. But hold on folks – how good is this study really? Would you want to draw conclusions from this?

Dundar U, Solak O, Yigit I, Evcik D, Kavuncu V. (2009). Clinical effectiveness of aquatic exercise to treat chronic low back pain: a randomized controlled trial. Spine, 34 (14), 1436-1440


  1. Agree with many of your thoughts here, but I guess would like to highlight where hydrotherapy IS a useful tool in helping patients cope with chronic pain (including LBP).

    As you say, many patients arrive fearful, anticipating pain and reporting previous failure with an ‘exercise’ approach. And as we know one aspect of how we interpret pain (and other sensations) is around its context.

    So providing patients with a warm, ‘low impact’ environment that they associate with positive experience and reduced anticipation of failure is surely likely to increase the success of any intervention that takes places within there. Add in the positions you can achieve that are more difficult on dry land and you have some real positives to work with.

    Is it that much different to how we establish a baseline for a graduated reactivation programme – establish what is realistic on a ‘bad day’, and then build on their success and consistency?

    The crunch (for me) is therefore just the same as on dry land. You’ve got to progress. How many hydro programmes include daily catch up with a PT? How more likely is the message to go and wallow, and we’ll see where you are at in 4-6weeks?

    I would hope that for the majority of patients activity that starts in the pool progresses to daily exercise at home and carries over into function. Otherwise all you’ve done is confirmed their original (and often inaccurate) beliefs – they are at risk, need protecting and should really take it easy.

    I use a pool with some patients because they associate it with previous success, they identify it as healthy and active and their pain irritability is so high that many active movements are unrealistic initially. I also do it because I have access to a pool. There are plenty of pain clinics without such resources who seem to get just as good outcomes.


    1. My argument isn’t against hydrotherapy per se – it’s about this particular research design which has been published in a peer-reviewed journal but lacks methodological rigour. Sadly I’m sure that people will cite it as ‘evidence for’ when in fact it’s not evidence of anything much at all, except that people like being in water and being monitored by a physiotherapist. It doesn’t address whether the people did more over the long-term, without support, and in their own environment. With a more robust methodology we could determine whether hydrotherapy vs land-based activities with the same level of attention from a physiotherapist could arrive at the same outcome – in the meantime, I’m not ready to adopt it as a routine approach apart from enjoying my occasional spa!

  2. Here is the thing, I can’t disagree with you about the quality of the research. But how does it REALLY compare with any other research out there. People don’t do well in “controlled” studies. There are simply too many variables in anyone’s life.

    So the choices are either stop doing any research because we know that a true controlled study is not possible or do we accept anecdotal evidence in admittedly poorly controlled studies?

    I have been treating back pain for over 20 years and here is what I know. Treatment combined with movement therapy works. It works great. Do I need a study to show that is true or can I accept my own conclusion? People (including health care providers) need to stop getting caught up in the details and start doing what we all know works.

    I don’t care if they do hydrotherapy or for those who are scared of the water do yoga. As long as they do something.

    1. I agree with you that people need to move and feel confident that they’re helping themselves recover. I can’t agree with you around whether we should continue with research and instead rely on our own conclusions. Unfortunately people used to believe that ill health was all due to various biles and did bloodletting for years and years – and many people died. The people doing bloodletting seriously believed that what they did worked, they could probably recount example after example of people who got well after bloodletting – but, and here’s the big one, they were wrong. At the time ‘what we all know works’ was bloodletting – so everyone did it! It’s only through ongoing research like these examples on my blog that we all benefit. And yes, controlled studies are unlike ‘real world’ but they allow us to look at the components in isolation so we can understand more. After all, who would have known that simply drinking clean water could minimise the risk of cholera without someone doing a controlled study? At the same time I understand your frustration, clinicians who care about patients will carry on doing ‘what works’ until they’re shown some strong evidence that they should change their practice – and then there are the other sort who jump in and adopt every new thing before there is any firm evidence! Don’t stop reading the research, and don’t stop the researchers doing their thing – and when the evidence is there to change, change.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.