Asked by: Kelly Wilson, Great Yarmouth
A nasty tingling, burning, and often painful sensation that’s usually caused by cutting off the blood supply to a group of nerves. This typically happens if you sit or kneel awkwardly and put pressure on a blood vessel. When you move, the blood rushes back into the affected area, bringing much needed oxygen to muscles and nerves that were temporarily starved. Until things settle down, those nerves over-react, sending disorganised messages up to the brain, as though they were detecting lots of little stabs from a hot pin. Some people like to jump about to force the blood on as fast as possible. This makes the pain much worse, but gets it over quickly. Others prefer to stay still and wait for the pain to stop. Unlike this common type, some people get continuing pins and needles with no obvious cause. This can be a sign of serious disease needing treatment.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.