Richard O’Brien, MD – American College of Emergency Physicians

First­-aid rules for injuries can be confusing. Here is the lowdown…

Cold reduces inflammation. Apply cold to acute injuries, such as a newly sprained ankle or a pulled muscle.

Heat improves circulation. It’s best for chronic pain, such as from tight muscles or a sore back.

Alternate heat and cold if you have soft­ tissue damage and/or stretched ligaments, such as an ankle sprain. Heat aids in restoring range of motion.

Apply cold for 20 minutes per hour as desired for the first 24 hours.

The next day, apply warmth for 20 minutes per hour as desired. Caution: Don’t apply cold for more than 24 hours or warmth for more than 72 hours.

If inflammation continues beyond 72 hours, see a doctor.