Ice vs Heat: Which Should I Apply?

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September 28, 2022

When we incur an injury (through a sport, CrossFit or anything else), we have been taught that the natural response is to ice the injury, usually in combination with rest, compression and elevation (depending on the injury). This forms the acronym R.I.C.E, which is the standard advice most of us will have received from PTs, doctors and our P.E. teachers at school. However, there has been recent discussion over whether icing an injury is all that effective to promote recovery, with alternative methods such as heat therapy cited as a suitable alternative. So how do we know whether to ice an injury, or use heat?

The answer is that both methods can be useful when applied at the correct stage of an injury.

When to ice an injury

It is generally accepted that ice should be used following an acute injury within the first 48-72 hours of sustaining the injury. Acute injuries are sudden injuries that occur immediately or within hours and cause pain (or severe pain) as well as potential tenderness, swelling and inflammation of the afflicted area. Most of these injuries result from some sort of impact or trauma such as a fall, sprain, bruises and slight hyperextensions. In this instance, ice is considered to be the best option, and here’s why: Immediately after an acute injury occurs, inflammation and swelling takes place due to damaged soft tissues and broken blood vessels which leak blood into the affected area. Ice is a vaso-constrictor (it causes the blood vessels to narrow) and it limits internal bleeding at the injury site, thus decreasing any swelling and numbing the pain.  Although most medical professionals state that ice should not be applied for more than 20 minutes at a time, some people have argued that doing so could still be helpful. Despite having the least research attributed to this technique, the theory is that by applying ice for a longer duration will elicit an increase in blood flow to an affected area and trigger the ‘hunter reaction’. This occurs when extremities of the body are exposed to cold, as blood is shunted away from the exposed area to preserve body heat, before the body then flushes blood back to prevent that area from suffering frostbite. As the affected area is relatively small, the body can counter the temperature difference without incurring frostbite. The theory is that this will increase the rate of recovery of an injured area.

However, there are critics of this method and of using ice for acute injuries at all, with mobilitywod guru Kelly Starrett posting a compelling argument on his site as to why icing an injury is a bad idea. The argument is that icing an injury promotes fluid build-up in an affected area and restricts lymphatic flow, which is what removes all the waste products and excess fluid buildup caused by the inflammatory process. When the waste fluid is drained, healing can commence, so Starrett argues that using ice is counterproductive as it disrupts the inflammatory process from progressing, preventing the body from naturally removing the waste products in the area. Instead, Starrett suggests using the process of M.C.E: “Move safely when you can, what you can. Compress lymphatics and soft tissues (use bands, muscle contraction, clothing, normatec, etc.)  Elevate when you can.”

Studies appear to support the suggestion that prolonged exposure to ice to tissue enhances the lymphatic vessels’ permeability, causing “backflow” of waste fluid back into the injured area, worsening edema, and potentially extending healing time. However, there is a lack of studies that investigate the use of ice for shorter periods of time on specific acute sports injuries, with the evidence we do have suggesting that the use of ice is effective in decreasing pain, but provides scant information for any further conclusions.

When to use heat therapy

Heat treatment can typically be used in one of two ways. First, in regards to dealing with injuries, heat should be used for chronic, recurring injuries, or injuries that have no inflammation or swelling. While ice constricts blood vessels, heat will dilate them, increasing blood flow. This is why you don’t want to use heat when you have swelling in an affected area, as you don’t want to increase blood flow to an area that’s already overloaded with blood. Heat becomes useful in instances where mobility and/or range of motion is limited, as these conditions are often caused or exacerbated by insufficient blood flow. Heat will promote blood flow and nutrients to the area, providing some relief to those symptoms and promote healing.

The second manner in which heat can be used is before exercise to increase the elasticity of joint connective tissues and to stimulate blood flow.

Think of how squash players repeatedly smack the rubber ball against the wall to literally warm it up and increase its sponginess and elasticity. The application of heat can also serve to help relax tight muscles or muscle spasms. However, heat should not be used post-exercise, and the overuse of heat therapy or incorrect application (on acute injuries) can do more damaged than good. Heating treatments can be accomplished using heating pads or athletic hot packs, or even through the use of a hot, wet towel. It’s best to cycle the application of heat on and off, though you can generally go for periods up to 20 minutes up to half an hour.

These are the generally advised ways to use heat and/or ice when treating an injury, but it’s important to remember that there are no ‘fixed rules’ one can use for every situation. Treatment can depend on a number of factors, including (but not limited to):

  • Stage of injury/disease
  • Location of injury
  • General health/medical status of athlete
  • An individual’s preference (patients may be better with one versus the other, in the same manner Tylenol may work better than ibuprofen for some people)

If you ever have any serious doubts over which method to use, it’s always best to be properly evaluated by a physician to determine the best course of action for YOU. Listen to your body, and be safe in the box!

Original image courtesy of Flickr

About Damect Dominguez

Co-founder of BoxLife Magazine. Author: Training Day: 400+ Workouts to Incorporate in Your Training.

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