How does compression wear help with blood flow?
In: Biology
If you ever see someone with one or both legs that look much larger than what you’d expect, often times discolored (red splotches or bruising), that’s from blood pooling in their leg(s). Wearing compression socks/stockings pulls everything in tighter which forces the areas that blood travels through to be smaller and therefor raise it’s pressure and helps it return to the heart.
Said another way, if you compress your legs really tightly, blood can’t pool down there. Think of it like filing a water balloon. If you try to fill a water balloon while squeezing it, eventually the water is going to come back out the top.
Had surgery on my left foot last year, and infection set in and it was ugly and painful but finally healed. After that my foot ached for hours and nurse suggested a compression stocking. WOW, what a difference it made, and assume it prevents blood from settling there. They must work for others too, since easily found now in drug stores.
This is because of how veins work vs arteries. Arteries which carry oxygenated blood from the heart throughout your body are at the “start” of the system and have the most pressure from the heart behind them, they also have “pumps” built into the structure to help move the blood along through the system and into capillaries, they do not have “one way valves” because the pressure is enough to always keep the blood moving forwards.
Veins on the other hand are at the “end” of the system are return the blood to the heart and lungs to be oxygenated again. They have the least pressure from the heart and do not have any “pumping” mechanism other than blood pressure from the heart, they also contain the biological equivalent to a “one way valve” so the blood can only move in one direction. Because of the one way valve any pressure places on them causes the blood to be forced back towards the heart. This can be from compression clothing, such as diabetic socks, but also things like massage or even exercise and the flexing of muscles will put pressure onto the veins and because of the “one way valves” it will always direct that blood back to the heart, improving circulation.
So compression does not help “blood flow” per se, but up to a certain point it does assist with forcing blood through the veins and back to the heart, although too much compression can cut off circulation entirely.
Your veins need external pressure to make the blood flow, usually the muscles do the trick by tensing up and squeezing the veins, so compression wear adds more pressure to the veins making the blood flow. Blood can only flow in one direction inside the veins because of numerous valves inside them that only allow the blood to flow in the right way.
Blood is pushed through your arteries by your heart. But because blood vessels are flexible that pressure dissipates over long distances. So your heart isn’t pushing the blood as much in your veins. To help the venous blood get back to the heart they have one way valves that force the blood in the right direction when your muscles squeeze the veins during physical activity.
Compression limits the flexibility (expansion) of veins and increases how much they are squeezed to take advantage of the valves that force blood to move in the right direction.
Think of it this way, your heart does not *pull* blood up from your legs, it’s only built to *push* blood into your arteries. Veins are passive returns to the heart, it relies on higher pressure in the atereies to push blood back through the veins to the heart. Muscle action and one-way valves in the veins are also important, but not super relevant here.
The idea of compression is that when the extremities are compressed, there’s less volume for blood to hang around. Positive pressure from the arteries is enough to push blood back up the veins because there simply isn’t anywhere else for the blood to go.
Without compression, blood can hang around. Especially if you’re mostly sedentary, there just is not much happening to move the blood back up the veins, so it just pools.
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