Compression sleeves: Don't they cut off bloodflow?

So I am trying to understand the purpose of wearing compression sleeves on the arms or calves. Don’t they restrict blood flow, which is what you would NOT want while exercising?

I can’t respond for exercise, but as a post-surgical intervention, they help keep lymphatic fluid from pooling in the periphery.

I wore mine on my legs for 4 days after an operation.
The nurse told me it was to prevent blood clots.

Graduated compression actually increases blood flow under the right conditions. It also helps blood return from the extremities to the heart. I’ve worn calf sleeves and they helped my recovery from injury and helped prevent cramping.

They more “support” than “cut off” blood vessels.

In many of the sporting situations I’ve seen them used I suspect that they provide a placebo effect as much as any measurable benefit.

Athletes are a superstitious bunch and prone to having a go at anything slightly different that has a plausible backstory even if there is little or no evidence of a beneficial effect. Of course as long as the item in question doesn’t actively diminish performance then any positive, purely mental, effect can be taken as evidence of efficacy, and so the myth is built.

Things like Kinesiology taping or ice baths showing little if any evidence of their claimed benefits when the method is properly tested.

I suspect compression sleeves to be of the same nature but of course I could be wrong and the scientific method is there to be used by anyone who cares to claim otherwise.

If you have an injury, your body often induces swelling to immobilize the area, which causes pain. If you squeeze the area with ice or compression, it helps flush that stuff out and lessens the pain.

On long runs, fluids can pool in your lower legs, which can be uncomfortable or painful. Compression socks can help limit that from happening.

So it’s probably more for pain management and swelling reduction in specific situations rather than any sort of day-to-day benefit.

Compression sleeves help blood flow. Each pump of your heart pushes blood through the blood vessels, and also slightly expands the vessel. Compression sleeves restrict the amount that the vessels can dilate, resulting in more blood flow.

Their benefit seems to be much greater after exercise than during. Blood flow is already typically maximized while you’re exercising, but the compression helps once you finish exercising and blood flow would otherwise slow.