Heat or Ice? When to Use Heat or Cold for Injuries


Heat vs. Cold: Part 1

When to Use Heat and When to Use Cold or Ice


Determining whether you need heat or ice for an injury can difficult if you’re not schooled in the science behind heat and cold/ice and how they affect the body.

Here's the short answer:

Use heat for sore muscles, chronic pain, and stress. Use ice/cold for actual injuries – that is, for swelling, redness, or acute pain resulting from a twist or heavy impact.

You're probably wondering about the science behind this.

That's for part 2.

Heat vs. Cold: Part 2

How it Works: Why Heat for Chronic Pain and Why Cold for Acute Pain and Injuries?

Heat is better for chronic pain or stress-related pain because it:

  • Increases oxygen flow and nutrients to the muscles, helping to heal damaged tissue. 
  • Stimulates sensory receptors in the skin, which reduces pain signals to the brain and partially relieves discomfort.
  • Helps eliminate toxins.
  • Relaxes stiffness.

Cold is better for injuries because it:

  • Reduces swelling by constricting local blood vessels and decreasing tissue temperature, leading to significantly decreased blood-flow and significantly slower cell metabolism.    
  • Numbs pain via numbing of the nerve receptors from the decreased blood-flow.

Heat vs. Cold: Part 3

How to Apply Heat or Cold

Tips on Applying Heat

There are two type of heat therapy:

  1. Local heat
  2. Systemic heat

Local heat involves heating a specific spot on your body using a warm cloth, a heating pad, or a heated gel pack.

Systemic heat means raising the temperature of your entire body via a bath, jacuzzi, steam bath, or hot shower.

When applying heat therapy, it's key to:

1. Keep the heat source 'warm' not 'hot'.

Your heat source shouldn't be burning your skin. Remember, the desired effect is penetration into the muscles. Scalding yourself will not accomplish this.

2. Not apply the heat for too long or too short.

In many cases, the longer the heat is applied, the better. However, duration of heat application should be based on the type of and/or magnitude of injury.

For something like minor back tension or pain, a short interval of heat therapy (such as 15 to 20 minutes) may suffice. For more intense or painful injuries, longer application of heat (such as 30 minutes to 2 hours, or ever more) may work better.

It also depends on how patient you are and how willing you are to sit still. If sitting still and/or reading or watching TV isn't an option, know that there are many different types of heat wraps, many of which are made to stay on while moving.  Also, the best heat wraps will maintain their temperature for a long time.

If you're sensitive to heat, the amount of time you apply the heat should be shorter. Also - you may need to use a barrier and/or wrap the hot pack in a towel before applying if it's too hot. 

Tips on Applying Cold 

Cold or ice therapy should only be applied locally and should never be applied for more than 20 minutes at a time, 

Remember: you're not looking to induce hypothermia, you're looking to numb your pain and restrict blood flow to the injury.

Also - if you're extra sensitive to cold you should decrease your time. 

Cold therapy can be applied via:

  • An ice pack
  • A cold gel pack
  • A bag of frozen vegetables
  • A frozen towel
  • An ice massage

For an ice massage, using an ice cup will produce the desired effect in less time. There are plenty of ice cups you can buy, or you can just make it at home by simply putting ice in a plastic cup and freezing it. Place the ice cup directly on the injury and massage the injury with the cup. Ice massage therapy is commonly used for things such as minor lower back pain.


When using any kind of ice or cold therapy, it's key to remember to:

1. Always have a barrier.

Always have some kind of barrier between the ice and your skin. Pillow cases and thin towels or rags work well for this. 

2. Make sure your skin is dry before applying.

Applying ice or cold to wet skin will increase the chances of frostbite, so always make sure your skin is dry. 

3.. Get it on quickly.

The effectiveness of cold therapy is highest immediately after injury and declines significantly after about 48 hours. 

4. Elevate the injury. 

 Keeping the injured part  above the heart while icing will help reduce swelling even more. 

5. Count the minutes.

Be sure not to apply the ice for more than 20 minutes or you could be risking frostbite. 


If you need more information about using these modalities, give JOI a call at JOI-2000.