Heat & Cold

The Proper Use of Heat and Cold to Manage Pain

As a Physical Therapist, I have encountered many questions and misconceptions by my patients on when they should use heat or cold and its proper use. Heat and/or cold can be an easy, effective, and inexpensive way to help manage pain. However, it can also have some serious side effects if not used correctly. In this newsletter, I will try to establish some guidelines on when to use heat and cold and the proper way to use these interventions in order to achieve the maximum benefits. So let?s get started.

When to use cold.

Cold can be an ice pack or a purchased product you place in your freezer and reuse. Later, I will give you some tips on how to make your own reusable ice packs. There is some controversy on the time frame cold should be used after an injury. Generally, cold should be used the first 48 to 72 hours following an acute injury. This means you should use cold rather than heat the first 2 to 3 days after an injury, such as joint sprain or muscle strain. The use of heat in this first days can cause increased swelling in the area and result in more pain.

After an injury is 2 to 3 days old, the body starts trying to heal the injury in a different way. It is then called a subacute injury. If the injury persists over a week, the body?s healing process then turns to yet another means of healing. This is called the chronic stage. The chronic stage persists as long as the injury is present. In the subacute and chronic stages of healing, both cold and heat can be of benefit. Cold may continue to be of more benefit when swelling remains in the area. Many times cold used during these stages can be more beneficial in reducing swelling over heat. Cold can also be very useful when muscle spasms are present. Some people are sensitive to heat and do not tolerate heat very well. If this is the case, then ice may work better.

How to use cold

These tips for the proper use of cold apply no matter what type of cold you are using. First, cold should only be applied for 15 to 20 minutes at a time. In most cases, whatever type of cold application you are using will have thawed by this time so there is little risk of the complications discussed below. What you don?t want to do is keep reapplying new cold packs one behind the other so the total time of the cold treatment exceeds 15 to 20 minutes. More is not better in this situation. If you do this, then you will over freeze the area decreasing the circulation to the area too much and could very well end up with a nasty case of frostbite. You can also wind up over cooling the nerves in the area end up with damage to the nerves. However, you can reapply cold several times a day. Once your cold pack has been off for approximately an hour and a half to two hours, it is safe to put on another cold pack. The effects of cold last longer than heat since it takes longer for the body to warm up than to cool off. In the acute stage of an injury, frequent application of cold in this manner can be very effective. Keeping the swelling to a minimum can speed up the body?s ability to heal itself. If you apply cold correctly, the area you e applied the cold pack to will become red. This is the normal response. If there are blotchy white spots in the red area after you remove a cold pack, this means that the area has been cooled excessively and is a warning sign. You should decrease the amount of time the cold pack is left on the next time.

Many people don?t like cold. They shiver just at the though of it. They cringe. They cry. Here?s a little tip if you feel this way about cold. Take a towel and wet it with warm water. Then wrap up the cold pack in this warm wet towel. Immediately apply the cold pack. The warm towel will help lessen the shock of having something frozen placed on your skin. You will feel the cold more gradually, making the cold pack application much more comfortable. This will also provide a moist cold instead of dry cold application which allows for deeper penetration of the cold and decreases the risk of over cooling the tissues resulting in unwanted side effects. As a Physical Therapist, I always apply moist cold.

When not to use cold

You should not use cold if you are cold insensitive. In rare cases, people are cold insensitive and have a reaction that is similar to an allergic reaction. If you just have a real aversion to cold, then you should not use it. This is especially true if you?re using the cold to relax muscle spasms. If you tense up your whole body just thinking about cold, what?s the benefit? You?ll just end up making the muscle spasms worse.

If you have a medical condition that effects circulation, then you should definitely NOT use cold. Some of these conditions include: Raynaud?s Disease, systemic lupus erythematous (SLE), peripheral vascular disease (PVD), scleroderma, or Bueger?s Disease (thromboangitis obliterans). If you think you may have a circulatory condition which would make the use of cold inappropriate, then consult your physician.

Cold should be used cautiously over areas that have previously been frostbitten, if you have high blood pressure (hypertension), in certain heart (cardiac) conditions, or over areas where there is nerve damage (neuropraxia). If you have one of these conditions, then you should consult your physician prior to the use of cold.

Other Useful Tips

You can easily make your own reusable ice pack. The easiest way it to just place some ice in a Ziploc bag. Once the ice has melted, it?s time for the ice pack to come off. Then just place the Ziploc bag back in the freezer and it will be ready for the next time you need it.

You can also place a mixture of water and rubbing alcohol in a Ziploc bag. You should use about one part rubbing alcohol to four parts water. The rubbing alcohol will not freeze, so it will form a slush like mixture. This allows the ice pack to fit better around the area and can be more comfortable. Once you have finished using the ice pack, place it back in the freezer so it will be ready for the next use. You may want to double bag these to avoid leaks.

When to use heat

Heat should never be used during the first 48 to 72 hours after an injury. This can increase the circulation to the area too much increasing the swelling and microscopic bleeding causing the injury to worsen and the pain to increase. Heat can be very effective during the subacute and chronic stages on an injury. Heat can effectively decrease pain, promote healing by increasing circulation, help tight muscles or muscle spasms to relax, and prepare stiff joints for movement. Heat is probably one of the most frequently used methods for home pain management. Everyone has probably used some form of heat at some point in time to help sore, stiff muscles or joints. The effects of heat do not last as long as cold, but can give temporary relief for up to an hour or more. Some common types of heat used in the home include: hot showers or baths, heating pads, microwavable heat packs, and warm compresses. All of these types can be effective, but it is important to remember that all are considered forms of heat when following the guidelines for using heat appropriately. In other words, if you just took a 30 minute hot shower, then you should not immediately jump from the shower to your heating pad!

How to use heat

While heat is probably one of the most widely used home treatments, it is also probably one of the most incorrectly used treatments. This has to be one of my biggest pet peeves as a Physical Therapist. I have spent many hours trying to educate my patients in the safest and most beneficial uses of heat, and I have to admit in many cases to little avail. My philosophy is that if you are going to take the time to do something, then you should do it properly in order to get the desired results. Otherwise, why bother? So anyway, here goes. Heat is like cold; you don?t want to over heat the tissue are you can get some very bad results. Heat should only be applied for 20 to 30 minutes at a time. This means sleeping on the heating pad all night is a big no-no!!!!! I can hear some people saying “But I?ve done that for years!” Again, more is not always better. This is one of those times. Here is why. Heat does several things to the body. It increases the circulation and it effects the nervous system. You get on your heating pad and it feels great, so you stay on it for several hours. You feel pretty good while you?re on it. Then you take the heating pad off and you notice your muscles are sore and stiff, so you get back on it for several more hours. This turns into a vicious cycle. What is happening is that your nervous system is having a reflexive response called “rebound” where the body is trying to compensate for the tissues being overheated. This rebound will actually cause the muscles and joints to become stiff and sore increasing your pain and the reasons you are using the heat in the first place. So, use heat for 20 to 30 minutes. Let your muscles cool down for an hour to an hour and a half, and then reapply the heat. The other big problem with prolonged use of heat is the risk of burns. Even if you have your heating pad set on low, prolonged use can cause burning. The heat continues to accumulate is the tissues becoming hotter than the body can handle, and you end up with a burn. I have seen this happen numerous times.

Many people who use heat also use some type of analgesic rub or lotion. You should never use these rubs and heat at the same time. These rubs are basically a type of heat. They give warmth to the area and change the circulation to the area. This is a very quick way to give yourself a burn. If you have used a rub, then you should wait an hour or two before you use heat.

Like cold, heat penetrates more deeply if it is moist instead of dry. Anyone who has ever been through a Physical Therapy or chiropractic program knows how wonderful the hot packs feel. That?s because they use moist heat. You can get moist heat at home also. There are several commercial moist heating pads available on the market today. A hot compress is a form of moist heat. You will have to rewet the towel several times with warm water however since it will cool off fairly rapidly. If you have a regular heating pad, you can make your own moist heat. Place the heating pad in a plastic protective bag (you don?t want to shock yourself!). Moisten a towel with warm water, wringing out the excess water well. Place the moist towel next to your skin and the heating pad wrapped in the plastic bag over the towel. If you use a microwavable form of heat, you can also wrap that in a warm moist towel to get the benefits of moist heat.

You should check the area you are heating frequently to be sure it is not overheating and trying to burn. Once you remove heat, the redness should disappear after 20 minutes or so. If it does not then it means that the area overheated and was trying to burn. It the redness is still there the next day, you gave yourself a first degree burn. Never place heat on an area that is still red from a previous heat application!

When not to use heat

Heat should not be used in the acute stage of an injury.

Heat should not be used by persons who have decreased or impaired sensation. Some common instances where impaired sensation may be present include: diabetes with neuropathies, stroke, head injury, and nerve damage.

Heat should not be used where there is compromised circulation. This could include peripheral vascular disease (PVD), arterial insufficiency, cardiac conditions, and diabetes.

Heat should not be used over malignant tumors.

Heat should not be used over open wounds or areas of suspected infection.

Heat should not be used over an area that has moderate or severe swelling (edema).

Heat should not be used over skin conditions.

Heat should not be used with acute inflammation.

This article has been reprinted by permission. It was published in the ezine Health Tips For Your Life newsletter provided by KAS Enterprises. The author is Kellie Stevens, P.T. who has worked in the health care field for almost 20 years. The topic of this article is the proper and easy ways to manage pain at home by yourself. To subscribe to Health Tips For Your Life click here.