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, ...

Infectious agents can cause muscle twitching and spasms, too. The most commonly known is probably tetanus, which causes a phenomenon called lockjaw, where the neck and jaw muscles contract to the ...

People with high-functioning anxiety often excel at work but feel they lack a greater purpose. Could you have high-functioning anxiety?

Twitching at night—it’s something few of us talk about, yet it’s also a phenomenon that impacts Americans when it comes to sleep quality. And even if you feel like you’re getting enough sleep, you ...