How is it that people suddenly twitch when they sleep?
This is biologically known as sleep twitch: involuntary contracture twitch of muscles and "jump" of limbs similar to twitch when going to sleep. It often feels like falling from a high place, or accompanied by vague dreams, which is likely to lead to waking up. Children and people with irregular sleep time have a higher incidence.
Normal people may feel one or two sleep twitches a day, and more non intense twitches will not be detected by us in our sleep. There is evidence that excessive stress or irregular sleep can lead to more sleep twitches, but as a harmless normal physiological phenomenon, it is not a problem to twitch more than once. However, if the twitch lasts every 20 to 40 seconds, it is no longer a sleep twitch, but a sleep disorder called periodic limb movement disorder.
[sleep twitch principle]
This twitch phenomenon in sleep belongs to a kind of conditioned reflex. Sleep twitch usually occurs when people sleep in a sleep position that has a burden on the body, which belongs to one of the manifestations of sleep disorder. When falling asleep, most of the nerves in the cerebral cortex are in a state of inhibition, but some of them are still active and send out some weak motor instructions to cause calf twitch.