When your foot falls asleep during a meeting for the millionth time, your first thought might be poor circulation — and you'd be sort of right. But the actual mechanism behind paresthesia (technical term for when a limb falls asleep) is a little more complicated. Normally, your nerves send signals that are interpreted by your brain as physical sensations (e.g. pressure or temperature). And when you're sitting in a less-than-ideal position, you might accidentally be compressing the nerves and making it a lot harder for them to communicate those signals. But circulation plays a role here, too: That compression actually reduces the blood flow to the nerves, which is what makes it harder for your nerves to send their messages. Instead they end up sending confusing and intermittent signals, which your brain interprets as tingling or just numbness. And voila — you end up with that characteristic pins-and-needles feeling. However, because the difference in blood flow that's responsible for paresthesia is caused by temporary pressure, trying to improve your overall circulation likely won't help. You should be able to get feeling back in a few minutes by simply changing positions because that will release the pressure. But if your numbness lasts for more than a few minutes or you consistently feel numbness, tingling, or a burning sensation in one part of your body, there may be something more serious going on. Sometimes, numbness that comes and goes every day is just a result of a chronic pressure on the nerve. That's the case with carpal tunnel syndrome and meralgia paresthetica, a common condition in which a pinched nerve in your pelvic area causes painful tingling or burning felt in your outer thigh. In those scenarios, you may need to adjust certain habits, such as making sure to stretch when you're stuck typing for hours on end, or even wearing more loose-fitting clothing. Other conditions can cause paresthesia or make it more likely, including diabetes or kidney disease and, rarely, a tumor pressing on a nerve (again, rarely!). Of course, letting that numbness go on for hours can be damaging, too, even if it's not due to some other scary condition. So, in most cases, your pins-and-needles will go away when you relieve the pressure on your nerves and you don't need to be concerned. But if it doesn't go away or keeps coming back, that's worth talking to your doctor about. At least it'll get you walking — and out of that boring meeting.