The twitching experienced when falling asleep is most commonly caused by hypnic jerks, also known as hypnagogic jerks or sleep starts. These are sudden, involuntary muscle contractions that occur as the body transitions from wakefulness to sleep. This twitching often feels like a jolt or a falling sensation and is a normal part of the sleep process. It happens because as the brain shifts from being awake to falling asleep, it can misinterpret the muscle relaxation signals and respond with a sudden muscle contraction, sometimes as a reflex to a perceived "fall" or loss of balance. Several factors can increase the likelihood of experiencing hypnic jerks, including caffeine consumption close to bedtime, physical exercise right before sleep, stress, anxiety, sleep deprivation, and certain medications affecting the nervous system. For most people, these twitches are harmless, but if they occur frequently enough to disturb sleep quality, consulting a healthcare provider may be advisable. In summary, twitching during sleep is typically a normal involuntary reaction as your body relaxes when falling asleep, often triggered or intensified by lifestyle factors like stress and stimulants.