Ice application to an injury may have negative effects such as blood and lymphatic fluid sludging and clotting, impeding debris removal and inflammation resolution.

“the ice is really more of a placebo. It numbs the environment of the injury, which is not surprising, and will eliminate the pain for a short while, but it has some negative effects that perhaps offset its use. One, it sludges, it creates sludging within the blood and other lymphatic tissue, so it actually can create some clotting and sludging of the tissue and fluids, the fascial interface with muscle, and a number of the stuff that's supposed to be flowing through there can slow up and increase inflammation in the wrong way, can actually restrict movement out of the injury site, which is bad because you want the macrophages and the other cell types phagocytosing, eating up, the debris in an injury and moving it out of there so that it can repair.”