Adrenaline increases the "alertness" of the nervous system, meaning it's ready to trigger muscle contraction. It also increases the amount of blood flow and changes the tension of the muscles, which, ...

Have you ever felt your eyelid suddenly flutter or twitch uncontrollably? This common annoyance, called eye twitching (or myokymia), is usually harmless and fades quickly. But when it persists, you ...