Swim failure
Also: swim failure
After a few minutes in cold water, arms and legs cool so much that you can no longer swim, even as a good swimmer.
Wikipedia describes this phase from about 3 minutes as cooling of the superficial muscles and nerves. Hence the rule: use the first minutes after cold shock for self-rescue and wear a PFD, because it keeps you afloat even then.
Sources and further reading
Research as of 13 Nov 2026. We have marked manufacturer information as such.