Applying ice to a fresh heat injury or other new soft-tissue injury usually helps at first because it can reduce swelling, pain, and inflammation by narrowing blood vessels. Applying heat too early can do the opposite and may worsen swelling or inflammation.

What ice does

  • Lowers blood flow to the area.
  • Reduces swelling and bruising.
  • Numbs pain for short-term relief.

When ice is useful

  • Right after an acute injury, like a sprain, strain, bump, or bruise.
  • Usually for about 10 to 20 minutes at a time, with breaks between sessions.

What to avoid

  • Do not put ice directly on bare skin.
  • Do not ice for too long, because it can irritate or damage skin.
  • If the area is very swollen, heat is usually the wrong choice early on because it can increase inflammation.

Simple rule

For a new injury: ice first, heat later. Heat is generally better after swelling goes down or for stiffness and chronic muscle tightness.

Get medical help

If the injury is severe, deformed, very painful, numb, or not improving, it should be evaluated by a clinician.