Both heat and ice treatments are useful ways to reduce pain. There is, however, a lot of confusion about which to use at any given time.
A GENERAL GUIDE
Use COLD treatment (cryotherapy) for a new injury where there is inflammation to the more superficial tissues of the body (e.g. a sprained ankle tendon or knee ligament), resulting in sensitivity, redness, swelling and acute pain. Ice numbs the injury. Cold narrows blood vessels and slows down blood flow, which can reduce inflammation and fluid build-up in the affected area and thus relieve the pain.
Use HEAT treatment (thermotherapy) for chronic (i.e. persistent or recurrent) pain, or for an injury that’s more than a day old. Heat can ease the pain of muscle spasms and knots (trigger points) in the muscles, or conditions that are dominated by them like back and neck pain. Heat is relaxing which is why overworked muscles respond best to heat. Heat stimulates blood flow, helps eliminate toxins, e.g. excess lactic acid, relaxes spasms, and soothes sore muscles. It also soothes the nervous system; helpful given stress and anxiety are major factors in many chronic pain problems.
EXCEPTIONS TO THE RULES
If you’re supposed to ice injuries, but not muscle pain, what do you with injured muscles, i.e. a muscle tear or muscle strain? The answer is to ice but only for the first few days at most, and only if it really is a true muscle injury. A true muscle injury usually involves an obvious trauma during intense effort, and sudden severe pain. If the muscle is truly torn, then use ice to start with to take the edge off the inflammation. Once the worst is over, switch to heat.
With lower back and neck pain it is best to err on the side of heat therapy rather than icing. The majority of low back pain is not caused by inflammation or any kind of trauma, but by the pain of muscular trigger points or knots. Trigger points generally dislike cold. Chilling the skin is actually a well known risk factor for the formation and aggravation of trigger points. Cold applied to the skin stimulates a reflex that causes muscles to contract; the last thing you want to happen if your back pain is caused by tight muscles. Applying heat to the skin triggers a mild reflex that reduces muscle tension.
Some back or neck pain caused by an obvious trauma, e.g. a fall can benefit from icing then heating immediately afterwards. A client experiencing lower back pain as a result of a fall, applied an ice pack locally in the area around her SI joints for 20 minutes to reduce the inflammation of the soft tissues caused by the impact trauma. Immediately afterwards she applied a hot water bottle to the same area to try and avoid the back muscles nearby spasming in response to the ice. This provided relief from the pain and assisted the healing process.
General rules and exceptions to those rules out the way, let’s consider the two treatments in a bit more detail.
There are two types of heat therapy…
Local heat is applied to a specific area by means of a hot water bottle, heating pad, hot, damp towel or a heat wrap.
Systemic heat involves a hot bath, sauna, steam bath or hot shower to raise the temperature of the whole body.
When applying local heat, avoid direct contact with the heating device, e.g. wrap a hot water bottle in a towel to prevent burns. During systemic heat therapy, remember to stay hydrated and avoid prolonged exposure.
If you suffer from an ongoing muscle injury, applying heat before exercising can be helpful. However, applying heat after exercise can aggravate existing pain.
For a more detailed look at heat therapy, check out this article on the Pain Science website.
Cold therapy is mostly applied locally. It should never be used for more than 20 minutes at a time because an excessive use of cold can cause tissue damage. You can apply cold using an ice pack, an ice towel (a damp towel that has been sealed in plastic and placed in the freezer for about 15 minutes), an ice massage, a cold gel pack or a bag of frozen vegetables.
It’s often beneficial to apply cold locally immediately after injury or intense, high-impact exercise to help relieve any inflammation or pain that occurs; this is a form of acute inflammation. Unlike heat, you can apply ice after going for a run. Cold treatment can reduce post-exercise inflammation.
Always wrap ice packs in a towel before applying to an affected area. It’s safe to repeatedly ice painful or swollen tissues but give your body a break between sessions. Do not use ice in areas where you have circulation problems.
Cold therapy can be applied systemically after an intense period of exercise. Ice baths are often used by athletes to reduce inflammation and pain that occurs after a sports activity. Again, this should not be done for an excessive length of time.
For a more detailed look at cryotherapy, check out this article on the Pain Science website.
WHEN TO AVOID ICE AND HEAT TREATMENTS
Both ice and heat are pointless or worse when unwanted, i.e. icing when you’re already shivering, or heating when you’re already sweating. The nervous system may interpret an excess of either one as a threat and in response, increase the pain.
Heat and inflammation are a particularly bad combination. If you add heat to a fresh injury, e.g. an injured knee, it will most likely increase the pain and swelling.
Icing painful muscles can cause a similarly adverse reaction. Cold therapy can aggravate muscle pain and stiffness, which are often present in low back and neck pain. Trigger point pain can be surprisingly intense and as such, easily mistaken for an “iceable” injury and inflammation. But if you ice these painfully sensitive spots in the muscles, they may burn and ache even more acutely. This mistake is made often with low back and neck, the very condition people often try to treat with ice.
Ultimately, it’s important to use whatever treatment feels best and works well for you. Your own preference is the most important consideration. Heat won’t help if you already feel hot and don’t want to be heated. And ice is unlikely to be effective if you have a chill or are cold and hate the idea of being iced. If you start to use one and you don’t like the feel of it or it doesn’t seem to be relieving the pain, try the other.
And if all else fails, you could take Jolie Holland’s advice…here’s a good cover of Holland’s fab song by Tom McKean & the Emperors…