The sudden jerking movement that you may experience while falling asleep is known as a hypnic jerk or a sleep start. It is a completely normal and common occurrence that affects many people.
When you fall asleep, your body goes through various stages of sleep, and during the transition from wakefulness to sleep, your brain waves slow down, and your muscles begin to relax.
However, sometimes during this transition, your brain may misinterpret the relaxation of your muscles as a signal that you are falling, and it may send a jolt of electrical activity through your body to wake you up and prevent you from falling.
This is the hypnic jerk, and it can happen to anyone, regardless of age or gender. It may be more common in people who are sleep-deprived, anxious, or fatigued. However, it is generally not a cause for concern unless it is happening frequently and disrupting your sleep.
If you find that your hypnic jerks are affecting your sleep quality or causing you anxiety, there are things you can do to reduce their occurrence, such as practicing relaxation techniques before bedtime, avoiding caffeine and stimulating activities before bed, and maintaining a regular sleep schedule.