Circulation
Blood flow to tied limbs; when rope restricts it, the usual signs are numbness and then pins and needles, which normally fade soon after release and can mask nerve compression.
Rope 365 calls restricted circulation very common in bondage: the usual first sign is numbness of the whole limb beyond the rope, followed by pins and needles as blood returns, and both normally fade within minutes of release. Because that numbness can hide nerve compression, the two need to be told apart. The ESINEM Shibari Classes course lists hands or feet growing colder than at the start and a nail that is slow to turn pink again after pressing; clinicians use the same nail-blanch check, the capillary refill test, as a measure of blood flow to the extremities. Sources disagree on color: the course treats a marked color change across a binding as a classic sign, while Rope 365 calls skin color an unreliable guide because it varies so much between people and relies on communication instead.