Your examples don’t seem to involve acute injury, just spontaneous swelling. They also seem to be specifically about the lower limbs, so I’m going to give an answer that addresses that stuff in particular. Swelling due to injury involves extra things that others have covered, so I won’t.
When blood is pooling in your legs and feet, it’s not circulating throughout your body correctly. Not only does this mean that your blood is unevenly distributed (your brain needs the blood, but it’s in your feet!), but you’re not moving blood and fluids around to get reoxygenated and waste filtered out.
There’s an increased chance of clots forming, veins deforming, and tissue damage (due to the aforementioned lack of oxygenation and waste removal) when blood is pooling in your feet.
So, compression, ice, and elevation are all to restore normal circulation of the blood and prevent clots, vein and tissue damage, and complications related to insufficient blood in the brain (stuff like fainting, or activating your fight/flight response that will increase your heart rate).
Latest Answers