Hydro questions

Question 1

What are the benefits of hydrotherapy?

Answer 1

Result of the physiological effects of both the immersion and the exercise

Question 2

Define:

Hydrostatics and Hydrodynamics

Answer 2

These principals define the environment in which we manage the patient, have implications for safety and for effective and varied treatment

Question 3

Relative density

Answer 3

Relative Density (RD) of water =1, if RD >1 = sink, if RD<1 = float
Human Body density is 0.87-0.97 so it generally floats
Lung = 0.95, Muscle = 1.06, Bone = 1.56, Fat = 0.09

Also consider osteoporosis, obesity, muscle atrophy, prosthesis, amputee, joint replacement, equipment (air filled).

Question 4

What is Hydrostatic pressure?

Answer 4

Hydrostatic pressure results in a fluid shift, and CV and lunge volume changes. Pressure at the feet is 10% greater than the upper body when standing in water. Hydrostatic pressure is useful for lower limb swelling.

Question 5

Pascal’s law

Answer 5

When there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container.
This pressure increases in proportion to the depth of fluid.

Question 6

Buoyancy

Answer 6

Buoyancy is the force experienced as an upthrust which acts in the opposite direction to gravity. It is equal to the weight of the water displaced.
A person with a specific gravity of 0.97 will reach stability when 97% of their volume is submerged.

Body weight percentages at different depths
65% at mid thigh
50% at waist
25% at mid chest
10% at shoulder depth

Clinical uses – decrease stress and compression, assist weak muscles.

Question 7

Drag force

Answer 7

Drag force relates to the viscosity of the water and turbulence. Turbulence = non stream lined flow.
Viscosity is the friction between adjacent layers of fluid.
Viscosity of water provides resistance to movement, resistance occurs against direction of movement.
Resistance increases proportional to speed and frontal surface area.
At slow speeds the resistance mainly comes from the viscosity of the water. Turbulence increases with increased surface area and increased velocity of movement. There are many ways we can use this clinically to assist us in hydrotherapy exercise.

Question 8

Specific gravity of the human body

Answer 8

Centre of Gravity
• point which all the mass of the body is balanced
• point through which gravity exerts its force downward
• can be localised between L4 and S2 levels
Centre of buoyancy
• Centre of the volume of the body

Effects on the body:
• 700ml central shift of blood pooling in the limbs to thorax and central circulation when standing upright
• 20-40% increase central blood volume
• 30-60% increase in cardiac volume
• 60% increase in cardiac output
• 30% increase in heart size (within 6 seconds of immersion)
• Increased pulmonary arterial pressure
• Increased end diastolic filling pressure
• Pulse rate stays stable

• Urine out put:
o 1mL/minute normally
o 6mL/minute after 1hr of vertical immersion

• Respiration
o Increase central blood volume→ ↓ lung compliance
o Upward displacement of abdomen ↓ FRC
o Increase in pressure of the H2¬O on the chest wall
o Increase in the work required to breath with increased perfusion BUT decrease in ventilation
o Estimated of about 10% increase in work of breathing
o Decreases exercise induced asthma due to high humidity

• Temperature
o Water has specific heat of 4 x that of air = retains 4 x as much thermal energy as air
o Thermal conductivity of 25 x air = transfers thermal energy 25 x faster than air.
o Stationary water transfers heat by conduction, moving water or patient by conduction and convection.
o Core body temperature: ~37C
o Skin Temperature: 32-33C
o Thermo neutral temp between 33-35*C
o Increase in outside temp = increase in blood pressure, heart rate and core temperature

When Exercising:
• Normally the body releases any heat produced through the skin. This relies on the outside temperature being less than the body temperature.
• When in the pool- the temperature is “thermo neutral”: i.e. the same temperature outside the body as inside the body. There is therefore no way for heat to escape from the body.
• A healthy young adult, standing still in the water- will get an increase in their core temperature after 3 hours. When exercising this temperature change occurs much earlier.
• If there is any compromise to the adult- such as blood pressure irregularities, recent surgery, decrease in fitness or even an increase in age, the core temperature can change sooner.

Question 9

Research behind exercise and water therapy

Answer 9

• Heart rate increases to a higher rate compared to when exercising on land.
• Heart rate increase is proportional to the temperature of the water.
• Frequency of breathing increases more than on land.
• Increase in water temperature, puts a higher load on the heart and lungs.

Question 10

Hydrotherapy uses

Answer 10

• Increase circulation
• Increase muscle strength
• Increase joint ROM, flexibility
• Improve ambulation
• Improve coordination
• Increase cardiovascular, respiratory conditioning
• Decrease pain, spasm
• Decrease weight bearing on joints
• Relaxation/psychological well-being

Question 11

Contraindications

Answer 11

Bleeding, Cardiac instability, UTI’s, Plantar warts, Tinea, Bladder or Bowel incontinence, Severe epilepsy.

Question 12

Precautions

Answer 12

Impaired thermal sensation and regulation (elderly and infant), infection, confusion or impaired cognition, recent skin grafts, after ingestion of alcohol, patients with fear of water, respiratory problems, pregnancy, MS.

Question 13

Conclusions

Answer 13

• Exercise in water should be for only 30-45 minutes.
• If feeling at all unwell- DO NOT ENTER THE WATER
• Go to the toilet before and after a swim.
• Ensure you drink water before and after hydrotherapy