These jerks are involuntary, meaning the person is not willfully making their body to move. In fact, they are described as muscle contractions felt in the entire body, or certain area, like the arms or the legs.When falling asleep, the muscles relax entirely so the brain mistakenly assumes the person is really falling and reacts by twitching the muscles.

Although these twitches are harmless, they can sometimes affect the person’s quality of sleep.

Researchers suggest that stress, caffeine, or physical exhaustion can make these jerks more frequent. Additionally, hypnic jerks can be triggered by sleep deprivation, vigorous exercise at night, and excessive nicotine consumption.Around 75% of the population has experienced these twitches during their lifetime.