One of the most common sports-medicine questions is whether to ice or heat an injury. Both techniques can provide short-term pain relief, but the trick is knowing which one to use and when.
How They Work
- Put simply, heat and ice manipulate blood flow—they just do it in different ways.
- Ice is what is known as a vasoconstrictor, which is a fancy word that means it reduces blood flow by causing blood vessels to narrow. This limits internal bleeding at the site of the injury and reduces swelling and pain.
- In contrast, heat is a vasodilator—meaning that it increases the diameter of blood vessels, thereby increasing blood flow. This increases circulation, which in turn increases the supply of oxygen to the injury site and accelerates the removal of waste products. Heat can help relax muscle tissues, relieve joint stiffness, and reduce muscle spasm.
How Do You Know Which One to Use?
The nature of your injury will determine whether you need to use ice or heat for pain relief.
- Acute injury: If you have an acute injury with pain and swelling, ice might be appropriate. Acute injuries are often the result of trauma or impact and can include sprains, fractures, and other injuries. They are usually accompanied by pain, swelling, and tenderness.
- Chronic injury: Chronic injuries are more subtle and slower to develop and are often the result of overuse. If you suffer from a chronic injury, you might benefit from using heat therapy. Chronic injuries often include sore, stiff, nagging muscle or joint pain.
How to Apply Ice or Heat
- Ice: If you have swelling or pain, wrap ice (or an ice pack) in a thin towel and apply it to the affected area for about 20 minutes. You may want to ice the injury several times a day during the first few days after injury. Just be sure to allow the skin to return to its normal appearance and temperature between icing sessions.
- Heat: As long as you have no inflammation or swelling, you can apply heat to relieve short-term pain. Moist heat is best, so you could use a hot, wet towel, but a heating pad or hot water bottle can work, too. Apply heat for about 15 to 30 minutes and be careful to avoid burns. Never leave heat on for more than 30 minutes at a time. Just like with ice, allow the skin to return to normal between sessions. Never apply heat if you have swelling or inflammation because it can slow recovery.
If your injury does not improve or grows worse within 48 hours, be sure to see a doctor.
