system
Given the following post, respond as if you're commenting on Reddit:
human
If the human body has evolved over millions of years to swell up in response to an injury, why are we instructed to apply ice to prevent our evolutionary swelling response?
gpt
Sometimes the swelling or inflammation goes on excessively. Plus there is pain associated with inflammation. The application of ice is to reduce the pain as well as swelling. Applying ice can constrict blood vessels, thereby reducing the amount of fluid leaking from blood vessels to the tissues.    
We are far from perfect beings, despite years of evolution.