The sudden feeling of falling off a tree and the body twitches as we try to fall asleep is known to all of us but ever wondered why they happen?
Body twitches, commonly also known as hypnic jerks or sleep starts, are scientifically called hypnagogic jerks which comes from the work hypnogogic. Hypnogogic refers to the transition phase when a body switches from wakefulness to sleep. The sudden muscle spasm is an immediate response to sleep by the body where the nerves “misfire” when the body goes through the transitional period. Many scientists believe that the primate reflex occurs in response to the relaxation of the muscles which the brain misinterprets as sign of the person falling off from the tree and hence it orders away the muscles to move immediately as a defense mechanism.
The sleep starts can increase in frequency if a person exercises a lot in the evening or can be induced by light, sound, anxiety and stress. However, more than often the sleep jerks are completely harmless and you should not be concerned with it as long as they are not interrupting your sleep.
Header Image: © Garo/Phanie/Corbis
h/t: Live Science