Applying ice packs to an injury can help ease pain and swelling, helping you recover more quickly. However, using an ice pack improperly can aggravate injuries and even cause serious health problems. Before applying ice to an injury, it's important to understand your risk factors and know how to use an ice pack safely.
Ice packs help relieve pain because the cold numbs the injured area. This numbing effect can be dangerous, however, because when you lose sensation in a part of your body, you have a difficult time noticing tissue damage. Placing an ice pack directly on your skin can cause ice burns, and leaving the ice pack in place over long periods of time can cause frostbite. In severe cases, doctors can only cure frostbite by amputating the dead tissue.
The Association of Chartered Physiotherapists in Sports Medicine recommends only using ice packs for a maximum of 10 minutes at a time on areas where the skin is close to the bone, and up to 30 minutes on areas with more fat or muscle. Always cover the ice pack or the affected area with a cloth, towel or elastic bandage.
Ice packs help reduce swelling by constricting blood vessels, slowing the blood's flow to the injured area. If you leave an ice pack on for too long, however, the opposite effect can occur. As the skin cools to below 59 degrees Fahrenheit, your body tries to counteract the effect of the ice by dilating the blood vessels and pumping more blood into the injury. This reflex helps prevent harmful effects of cold exposure, such as frostbite--but when you're dealing with an injury, it can cause further swelling and bleeding, negating the ice pack's initial benefits.
Not everyone can use an ice pack safely. Ice packs may cause or complicate other health conditions. Don't apply an ice pack on an area where you have numbness or decreased sensation. This may indicate another problem, such as a pinched nerve; using ice could mask the problem and prevent you from seeking treatment.
Never use an ice pack if you have high blood pressure or poor circulation. Because cold therapy constricts blood vessels, it decreases circulation and increases blood pressure. Finally, using an ice pack on a chest injury can constrict the blood vessels near your heart, causing angina pain.