when to ice

Best practice is to apply ice to an acute injury or new injury. An acute injury, such as a sprain, involves tissue damage and inflammation around the injury site. Acute injuries are short-term injuries. Some common acute injuries:

Ankle sprain
Knee sprain
Muscle or joint sprain
Red, hot or swollen body part
Acute pain after intense exercise

When you sprain something, like an ankle for instance, you damage blood vessels,” says Baer. “When blood vessels are damaged, swelling usually occurs. Applying something cold, whether it be ice or even a bag of frozen vegetables, causes the blood vessels to constrict, reducing the swelling