The fear of needles is one phobia that doesn't seem particularly irrational — shots hurt! Phobics and those with low pain thresholds might be pleased to know that those shots are getting pretty close to being pain-free, reports Popular Science.
A study presented at this year's annual meeting of the American Society of Anesthesiologists looked at ways to decrease needle pain in a small sample of 21 people. By adding vibration, pressure, or changes to the temperature, the researchers were able to make the injections hurt less. Although each of these changes was significantly better than nothing, none was markedly better than any other at reducing the pain caused by needle pokes.
According to the gate control theory of pain, signals heading toward the brain have to pass through "nerve gates" along the spinal cord. When there's actually a painful situation associated with the signal (such as, you know, being pricked with a needle), the gates open, the signal passes through easily, and we feel the pain as more intense. But, under normal circumstances, those physical sensations don't cause pain, meaning the gates remain closed. So, by following up a painful stimulus with a non-painful, but still physical one (such as rubbing your elbow after you bang it on something), the gates can be closed and the feeling of pain lessened. In this study, it's suggested that adding the extra element of vibration, for instance, reduces pain and makes the possibility of pain-free shots that much closer to reality.