Editor’s note: The following is based on recent research and should not be construed as medical advice. For questions, please contact a healthcare professional. Going back to the first real bumps and bruises we got in preschool, the best remedy was always to put an ice pack on it. In fact, just about any playground injury could be solved in seven to 10 minutes with some combination of a Band-Aid, a sandwich bag full of ice cubes, and a hug from the teacher. However, a new study out of McGill University is challenging one of the core medical assumptions about icing an injury. In a recent study published in the journal Anesthesiology, researchers injected mice with irritants into their paws and leg muscles to simulate injury. (Poor mice!) The mice were divided into groups whose legs were iced in 39°F water and groups whose legs were not. To the average person, the results were probably pretty surprising. A woman icing and elevating her arm. Photo credit: Canva How did the mice that got ice heal compared with those that did not? In the short term, the mice that received ice had less pain and inflammation than those that did not. However, the mice that received ice treatment three times a day for 30 minutes each took 40 days to fully recover. Those that received it just once for 60 minutes a day averaged 25 days. Those that received no ice at all recovered in roughly nine to 20 days. “These results highlight a paradox: treatments that reduce inflammation and relieve pain in the short term may, in some cases, interfere with the biological processes required for full recovery,” lead study author Lucas Lima, a research associate at the Alan Edwards Centre for Research on Pain, said in a statement. A child with an injured knee. Photo credit: Canva Why does icing an injury delay the healing process? The researchers on the “ice on mice” study found in prior studies that neutrophils—white blood cells that rush to the site of an injury—are inhibited when patients take anti-inflammatory medications such as Ibuprofen. The researchers speculate that when ice is applied to an injury, the same thing happens. The lack of neutrophils prevents the body from shutting down the pain response after the injury has healed. A woman icing her injured wrist. Photo credit: Canva The results of the study may take some people aback. But McGill University isn’t the only organization questioning whether we should apply ice to injuries. In a study titled “Is it the End of the Ice Age?”, the International Journal of Sports Physical Therapy questioned its efficacy. “…the efficacy of using ice as a recovery strategy following injury in humans remains uncertain, and there is a growing trend recommending against icing following injury,” Susan Y. Kwiecien wrote. “Animal models suggest that while ice can help to accelerate the recovery process, extreme muscle cooling might delay repair and increase muscle scarring.” Ultimately, much work remains to be done before we stop using ice to ease pain and inflammation altogether. “Our results suggest we need to better understand when anti-inflammatory strategies are helpful and when they are not,” senior study author Jeffrey Mogil, a James McGill Distinguished Professor and E. P. Taylor Chair in Pain Studies, concluded. The post Hurt your knee? New research says think twice before grabbing an ice pack. appeared first on Upworthy.