Here is a quick guide to when ice and when to heat.

As a general, use ice for fresh injuries, and heat for chronic muscle pain and stiffness. Cold helps numb sharp pain and reduce inflammation. Heat helps soothe stiff joints and relax muscles.

Both ice and heat have the potential to do harm when used poorly. If you add heat to a fresh injury, it’s going to get worse! And ice can aggravate symptoms of muscle tightness and stiffness.

ICE

Ice is for acute injuries. It works by reducing blood flow to a particular area. It can temporarily reduce nerve activity, which can also relieve pain. Ice treatment is most commonly used for recent injuries (within 48 hours). For a home treatment, wrap an ice pack in a towel. Applying an ice pack to the affected area early and often for the first 48 hours will help minimize swelling. 10 minutes each time is enough, and no more than 20 minutes to prevent nerve and tissue damage.

Precautions:
Never treat with ice for more than 30 minutes, and remove the pack immediately if the injury appears bright pink or red.

Never place ice directly on an injury; keep the pack moving to avoid ice burns.
Never apply a frozen item directly to the skin, as it can cause damage to the skin and tissues. For a quick home treatment, wrap an ice pack in a tea towel.

HEAT

After the inflammation has resolved, heat can be applied to ease stiffness. Heat therapy is often most beneficial when used for a good amount of time, unlike cold therapy which needs to be limited. Minor stiffness or tension can often be relieved with 15 to 20 minutes of heat therapy.

Heat treatments should be used for chronic conditions to help relax and loosen tissues and to stimulate blood flow to the area.

Precaution
Never use heat where swelling is involved because swelling is caused by bleeding in the tissue. Heat draws more blood to the area and aggravates the swelling.

Which is better?

Neither is strong medicine. Some experiments have shown that both heat and ice have only mild benefits. The reason to use them is not that they are highly effective treatments but because are rational, cheap, easy, safe self-treatment options for many common problems.