Heat or Ice for an injury?

Which one is appropriate or best? And when? Our Bethesda chiropractor can help.

What your body does...

• damaged tissues release a cascade of inflammatory cells, hormones, and chemicals to begin the healing process
• vasodilates (enlarged blood vessels bring more blood to the area)
• increases in warmth

What heat does...

• vasodilates (enlarges blood vessels bring more blood to the area)
• promotes the production of inflammatory chemicals
• can bring relief through muscle relaxation

What ice does...

• vasoconstricts (narrows blood vessels and redirects blood elsewhere)
• reduces inflammation if used during the first 48-ish hours of injury
• reduces pain (has been shown to reduce the use of pain medications)

Which one do I use?

Question: If heat mimics the natural healing processes of the body, and ice appears to do the opposite, wouldn't heat help healing and ice prevent healing?

It's not an apples to apples comparison because nuance and questions remain:

We can have acute injuries, where we see the inflammatory cascade and swelling. We can also have chronic injuries, in which the inflammatory process doesn't exist in a significant way.
Looking at it from this perspective, without any other context, acute injuries would still seem to be best treated with heat, whereas with chronic(old) injuries either could be used(it's really patient preference)

Most applications of heat don't increase the temperature of deeper structures. Dry heat and even moist heat are typically applied for 5-20 minutes, which is not enough time to heat up deeper muscles. To reach deeper structures, one would use moist heat for significantly longer periods of time

-and-

Ice therapy can change tissue temperatures at depths of up to 1-3 inches.
Compression enhances the effects.

Based on these two findings, we have to question that in the event of an injury that is deeper than 2-3 inches from the surface of the skin, would either therapy even affect the temperature at that tissue/joint/muscle?

Are there any medical conditions that would keep someone from using one or both? Diabetes, circulation problems, open wounds, infections, Raynaud's disease, peripheral vascular disease, inability to feel the skin, etc.

Assuming all else was equal, would a properly applied temperature therapy have a truly significant impact on healing time?

There are not any conclusive bodies of relevant research that say either way. Evidence exists on the localized physiological and metabolic reactions to the different temperature therapies(which are listed above), but not that display any significant enhancement or delay in healing time.

My official opinion is: Use whichever one you prefer!