Cold & Heat Therapy - Quick review

Energy transfer

  • How to convert between fahrenheit (F) and celsius (C)

    • F = (9/5 x C) + 32

    • C = 5/9 (F-32)

  • Conduction - when molecules interact

    • Thermal conductivity - varies with what medium is used

    • What affects conduction?

      • Tissue type

      • Tissue depth

      • Length of exposure

      • Temperature gradient

      • Activity

    • Effects of conduction

      • Vasoconstriction

      • Nerve conduction velocity decreases

      • Tissue temperature decreases

    • Specific heat = amount of energy that is needed in order to raise the temperature of an object at a specific weight a specific amount of degrees

      • High = water - needs more energy

      • Low = air - needs less energy

    • Modalities that use conduction

      • A larger difference in temperature = faster rate of conduction

      • The lower difference in temperature = longer time need to cool tissue

      • Skin - temperature drop takes about 15 min; Muscles - temperature drop can take about 1.5 hours

  • Convection

    • Direct contact between skin and fluid - heat abstraction - the movement of water

    • Vasodilation increases circulation, increased temperature --> reduces the risk of burning

  • Evaporation

    • Cooling of skin, extracting heat

      • Use when seeking temporary pain relief surrounding stretching treatments of muscle spasms

    • Decreases skin temperature, decreases motor neuron activity, deep tissue effects

Tissue cooling

  • Effects

    • Vasoconstriction (stimulate dorsal root ganglion)

    • Decrease blood flow

    • Decrease histamine and bradykinin = decrease vasodilation

    • Increase viscosity

    • Increase smooth muscle tone

  • Inflammatory effects

    • Decrease inflammation

    • Decrease pain

    • Decrease local metabolism

    • Decrease intramuscular pressure

  • Peripheral nerve effects

    • Decrease nerve conduction velocity

    • Increase pain threshold

  • Muscular and neuromuscular effects

    • When cooling is used for a short period of time = could increase muscular performance

    • When cooling is used for a longer period of time = decrease in strength, proprioception, and agility

    • Decreased spasticity

      • Decrease gamma motor neuron firing

      • Decrease afferent spindle discharge

Use of cryotherapy

  • When to use cryotherapy

    • RICE

    • DOMS

    • Pain

    • Muscle spasm

  • Explain the feeling of cryotherapy

    • Very cold --> Burning sensation --> Aching/discomfort --> Numbness

  • Rules of cryotherapy use

    • Evaluate what area of the body is being treated

    • Mindful of the previous injury

    • Do not stress area for up to two hours after treatment

    • Be mindful of numbness and discoloration

    • Be conscious of the time of use - do not exceed 20-30 minutes in one treatment

  • Contraindications

    • Sensitivity to cold

    • Cold urticaria

    • Raynaud's

    • Poor circulation

    • Nerve degeneration

  • Precautions

    • Hypertension

    • Sensitivity to cold

    • Impaired circulation and/or sensation

    • Open wounds

    • Superficial nerves

  • Types of treatment

    • Ice pack

    • Ice massage

    • Cold spray/gel

    • Cold tub

    • Cold compression unit

  • How to measure the effectiveness

    • Pain scale

    • Measurements of inflammation

    • ROM measurements

    • Functional movements

    • Assessment of muscle spasm/guarding

Heat therapy

  • Conduction

  • Convection

  • Radiation - conversion of heat energy

  • What determines how heat therapy affects tissue?

    • Tissue volume

    • What tissue is made of

    • Blood supply

    • How energy is transferred

    • Temperature rise

  • Ideal heat range for therapeutic heat = 104-113degrees

  • When there is an increase in temperature in tissue, what metabolic changes are seen?

    • Increased uptake in oxygen

    • Increased cellular activity

    • Increase in healing nutrients

    • Metabolic rate increases

  • Effects of heat therapy

    • Decrease pain

    • Increase ROM

    • Decrease stiffness

    • Decrease muscle spasm

    • Increase blood flow to the area

    • Promote healing

  • Effects on the vascular system

    • Vasodilation

    • Release of histamine and prostaglandins

    • Spinal cord reflexes

  • Neuromuscular effects

    • Increase nerve conduction velocity

    • Decrease pain and muscle spasm

    • Muscle spindle firing

  • Effects on connective tissue

    • Increased flexibility

      • Viscoelastic properties

    • Increased elasticity

    • Decreased viscosity

    • Decreased stiffness

Types of heat therapy

  • What modalities can be used to increase tissue temperature at a depth of 1-3cm?

    • Moist heat packs - conduction - easy to use but harder to control the temperature

    • Paraffin wax - slower heating, lower risk of burning, used on hands/feet

    • Warm whirlpool

    • Electric heat pad - low level of heat, easy to use but can cause burns

    • Air activated heat wraps - low profile, longer usage, cost-effective

    • Fluidotherapy - convection - easy to use but expensive and variable

  • What modalities can be used to increase tissue temperature at a depth of 1-5cm?

    • Ultrasound - continuous

    • Shortwave diathermy - continuous

Use of heat therapy

  • Contraindications

    • Malignancy

    • Infection

    • Acute inflammation

    • Decreased sensation

    • Vascular concerns

    • Hemorrhage

  • Determine if using heat therapy is appropriate for injury, body part, stage of healing, other conditions and etc