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Hydrotherapy or Aquatic Therapy is it for you?





Aquatic therapy is a key component to rehabilitation here at LiquidGym. It’s one of the things that makes us unique compared to other rehab settings! If you have had an aquatic therapy session before or are interested in trying it out, you might be asking yourself some questions like “why am I able to do more in the water versus on land?” or “how will water exercises help my injury in the long run?”.

What are the effects of water on the human body?

This blog is going to answer just that. We’ll dive into some of the effects that water has on the body, and why it is such a useful tool used by therapists to help treat various injuries. Dust off those high school textbooks because we’re about to talk about some aquatic physics!

What are some terms you should know?

1) Buoyancy



It is the upward force that acts on an object in the water. The deeper you go, the greater the upward force of buoyancy because of the increase in hydrostatic pressure with depth (more on that later). As you immerse yourself in water, you encounter different percentages of offload depending on how deep you are. For example:

  • If you go up to your knees, 25% of your bodyweight is offloaded
  • If you go up to your hips, 50% of your bodyweight is offloaded
  • If you go up to your shoulder, 85% of your bodyweight is offloaded
  • Takes pressure off your joints
  • Gravity can be partially or completely eliminated
  • Can be used to help someone with weight-bearing restrictions to begin to train their walking again

2) Temperature

A typical temperature for relaxation of the body sits between 36-41 degrees Celsius. Water can keep in heat better than the body, so at this temperature, there is a heat transfer to the body which causes our blood vessels to open up and relax.

  • A higher water temperature DECREASES pain because pain and temperature follow the exact same nerve pathways from the brain to the skin
  • In effect, temperature helps to “block” pain signalling by taking over the path on its own

3) Hydrostatic Pressure

It is the pressure that is exerted by the water on an object because of the downward effects of gravity. This pressure increases based on how deep you are in the water.

  • This pressure moves through your body, helping to eliminate swelling or edema in your limbs
  • This pressure exerted on your body is also great for strengthening your chest muscles because it increases the work of breathing

4) Turbulence & Drag Force

Turbulence refers to the motion that waves create and has to do with a wave’s changing velocity at variable times. Drag force refers to the force of a body moving through the water, which makes it harder to stay upright. Did you know? Water is 14x more resistant than air!

  • Great for balance and strength training


I know you talked about the water increasing the work of breathing- should I be concerned about using a therapy pool if I have a cardiac condition?

If you don’t do regular aerobic exercise, it is always a good idea to make sure you are cleared by your family Dr. beforehand. Clients with acute cardiac dysfunction, acute restrictive lung dysfunction and uncontrolled restrictive pulmonary disease should be cautious about engaging in physical activity in the pool because of the water’s effect on heart rate and breathing rate.

What are some other conditions that people may have that might limit their ability to participate in aquatic therapy?

As always, it is important to discuss your medical history both with your family Dr. and with your healthcare team to ensure that you can engage in physical activity in the pool in a healthy and safe way. In general, these are some of the conditions that would signal that a person is not ready to use the pool just yet:

  • Fever
  • Infection
  • Open wounds/surgical incisions
  • Contagious skin conditions
  • Incontinence
  • Diarrhea, vomiting
  • Uncontrolled seizure disorder
  • Uncontrolled cardiac conditions

How do I make exercises more challenging in the water?

There are a lot of ways to make things more challenging in the water! Here are 3 main ways to do this:

Surface area: the larger the surface area, the harder the resistance (think of the opposite of what you would want to do in order to be aerodynamic- such as using an open palm of your hand instead of slicing with your hand through the water).

Speed: the higher the speed of movement, the higher the resistance and drag force.

Water depth: decreasing your depth in the pool means that less of your bodyweight is offset by the buoyancy, which means you’re closer to land function!


Becker, B & Cole, A. 2010. Comprehensive Aquatic Therapy: 3rd Edition. Washington State University Publishing.

Bonnyman, A. 2016 May. Advanced Aquatic Physical Therapy: Evidence Based Practice. Canadian Aquatic Rehab Institute. Presented at LiquidGym, Ottawa ON.

Emma Lis

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