Use ice when the knee is swollen, warm or newly injured. Use heat when it is stiff and aching, for example arthritis in the morning. Apply either for 15 to 20 minutes with a cloth between the pack and your skin, up to a few times a day.
When ice helps
- In the first two to three days after a twist or knock
- After activity that makes an arthritic knee swell
- A bag of frozen peas wrapped in a thin towel works well
When heat helps
- Morning stiffness from arthritis
- Tight muscles around the knee before exercise
- A warm shower, heat pack or warm towel
When to avoid both
- Do not use heat on a hot, red, swollen knee. That can be gout or infection: see a doctor.
- Avoid either if you have poor feeling in the skin, for example from diabetes.
- Never sleep on a heating pad.
Some people switch between the two. Use whatever feels better, as long as the knee is not hot and red.