Cold and heat therapy are often used as a treatment for sprains, strains, pain and other injuries.
But how do you know when to use which? And is one better than the other?
The answer is that it depends. However, as a general rule of thumb:
- Ice is good for reducing swelling and inflammation
- Heat is good for relaxing and soothing muscle pain, chronic pain, or stiff muscles and joints
If used correctly, cold and heat therapy can help:
- Reduce pain
- Assist with tissue healing
- Control swelling
- Increase range of motion
If used incorrectly, however, these methods can worsen an injury or slow recovery times: heat therapy can make inflammation worse, and ice can aggravate tight or stiff muscles.
What is Cold Therapy?
Simply put, cold therapy reduces swelling and pain.
When an injury occurs, the surrounding soft tissue often bruises, swells and becomes inflamed.
When a cooling agent is applied to the skin, blood vessels constrict and blood flow decreases, reducing that swelling and inflammation.
Skin temperature goes down and nerve endings are numbed, which dulls the pain.
Common cooling options include:
- Ice packs
- Ice baths
- Ice cubes
- Crushed ice compresses
- Cold cloths
- Coolant sprays
- Frozen gel packs
How and When to Use Cold Therapy
Cold therapy is best within the first 48 hours after sudden acute injuries (such as from a sprain or strain or pulled or torn muscle), or for 3-5 days afterward, if inflammation persists.
Follow the PRICE protocol to manage an injury in the early stages when swelling and pain is at their peak: Protection, Rest, Ice, Compression, and Elevation.
Some additional tips:
- Use cold therapy for 10-15 minutes several times a day, but no more than 20 minutes
- Never apply a frozen item directly to the skin, as it can cause damage to the skin, tissues, and nerves – wrap the item in a towel first
- Cold therapy can also be used after an activity – not before – to prevent or reduce pain and swelling, control inflammation, or ease muscle spasms
What is Heat Therapy?
Heat therapy is used to relax and soothe muscle or joint pain and stiffness, chronic pain, and reduce muscle spasms.
Blood vessels dilate and increase blood flow to the area being heated, delivering needed nutrients and oxygen while aiding in the removal of cell waste and promoting healing.
There are two different types of heat therapy: dry heat and moist heat.
Both types of heat therapy should aim for “warm” as the ideal temperature instead of “hot.”
- Dry heat includes saunas, or items like dry heating packs, hot water bottles, gel packs, and electric heating pads which are best for local or small areas of pain
- Moist heat includes items like steamed towels, damp clay packs used in physiotherapy clinics and hospitals, or hot baths
- Moist heat is preferred over dry heat, since it penetrates deeper to reach muscles, ligaments, and joints
Therapeutic heat, such as from an ultrasound, is often used in the chronic phase of an injury. It is also used for relief from arthritis, muscle spasms, menstrual cramps, tendinitis, and more.
How and When to Use Heat Therapy
Heat therapy often works best for morning stiffness or to loosen muscles before an activity – not afterward – as it increases muscle flexibility and range of motion.
Some additional tips:
- Hot packs should be applied for 15 to 20 minutes – minor stiffness or tension can often be relieved in this timeframe
- Several layers of towels should be used as a barrier between the heating agent and the skin to help prevent skin irritation or burns
- A warm bath or sauna lasting between 30 minutes and two hours would be better for more severe or widespread pain
When Not to Use Cold and Heat Therapy
While cold and heat therapy is a good treatment option for many, they are generally not recommended for people with:
- Sensory disorders, because of an absence of skin sensitivity
- Impaired circulation or ischemia
- Diabetes because of possible nerve damage and lessened sensitivity
- Open or infected wounds
- Dermatitis or eczema
- Heart disease or hypertension – consult your doctor first
Cold therapy shouldn’t be used for people with vasospasm (Raynaud’s disease) or hypersensitivity to cold.
Heat therapy shouldn’t be used for people with vascular disease, deep vein thrombosis, multiple sclerosis, or cancer if treating the region over the tumor site.
Heat therapy should also be avoided in the acute phase of an injury when swelling or bruising is present and the skin is hot to touch or in an area of recent bleeding. If you experience increased swelling, stop treatment immediately.
When to Use Both Cold and Heat Therapy
Alternating between cold and heat therapy can give you relief from aches and pains caused by conditions like arthritis and fibromyalgia, and for an acute injury after the first 3-5 days of cold therapy.
Knowing when to use each therapy will significantly increase the effectiveness of the treatment.
If you’re still uncertain, or if you have pain that doesn’t improve within 48 hours, contact a physiotherapist near you to learn more about the best way to treat your symptoms.