We’ve all been there before… a fresh ankle sprain, a bump to the elbow, or a lower back tweak. What should you do?
As physical therapists, we’re often asked, “Should I apply ice or heat?” While heat might be more enticing in general, especially while it’s chilly outside, each modality does something unique and it’s important to know when to use them.
What does heat do?
There are many applications of heat which may be beneficial for therapeutic use. Heat dilates the blood vessels and increases blood flow to the area that’s being heated. This increase in blood flow causes an increase in oxygen and nutrient delivery, while also assisting in the removal of waste products. Another use for heat is to decrease joint stiffness and increase a muscle’s ability to stretch. This is helpful to remember since muscle warming can reduce the risk of injury.
So when can I use heat?
Heat is most useful to warm up tissues prior to stretching or exercise. Although applying a heat pack does warm up tissue, it is typically not as effective in increasing blood flow as light exercise is. For example, walking before you start running is a great way to warm up and prevent injury. 
It is not advisable to use a heat pack on any area that is swollen, bruised, red and inflamed, or acutely injured no matter how many days is has been since the injury. The increase in blood flow described above can bring more swelling and inflammation to the area being heated.
How do I use heat?
When using heat packs, the length of treatment time is dependent on how hot the heat pack is and how it’s being applied. When applying a microwaveable hot pack or electrical heating pad, it is a good idea to check on the area after about five minutes to see if the skin is reacting appropriately. Mild redness is expected after the application of heat, however, there should not be any blistering of the skin. Total treatment time should be between ten and twenty minutes.
What does ice do?
There are many instances when the use of therapeutic cold, or cryotherapy, is preferable. Ice causes the blood vessels to constrict, therefore, decreasing blood flow to the area where cold is applied. This decreases the presence of the inflammatory cells near the injured tissue resulting in less swelling and pain.
So when can I use ice?
Because ice decreases the blood flow to an area, it acts as a natural anti-inflammatory. Ice is best used when an injured area is swollen, warm, or inflamed, regardless of whether the injury is fresh or not. The age-old adage that you should only use ice for the first forty-eight hours post-injury does not apply to most injuries.
How can I use ice?
When using a cold pack, it is advised to have a barrier between the cold pack and skin to decrease the likelihood of cold burns. These include conventional cold packs with a gel or liquid filling, ice packs, and bags of frozen vegetables. These should be applied for ten to fifteen minutes or until numb. Ice cups can be used for ice massage which is performed by pressing the ice directly on the skin with light to moderate pressure, and moving it around. This should be done for a maximum of five minutes.
Even if it isn’t comfortable to put ice on an injured area (it is cold after all!), it is usually the best idea for most orthopedic injuries. One more thing to consider and keep in mind: if ibuprofen is helping your pain decrease, ice probably will too. Have a question? Call or email us, we’re happy to help!