The "hypnic jerks"

Everyone must have experienced this - the sensation of falling when half asleep and jerking yourself awake. There are many names you can use to call this, including hypnagogic jerk, sleep start, sleep twitch, myoclonic jerk, or night start, etc. But this common phenomenon is mostly known as the "hypnic jerk". From a scientific perspective, this is a brief and sudden involuntary contraction of the muscles of the body which occurs when a person is beginning to fall asleep.

Around 70% of people experience them at least once in their lives with 10% experiencing them daily. Although the exact cause of hypnic jerks is unknown, they are thought to be completely normal. However, stress, caffeine, or physical activity right before bedtime may make them worse. They occur more frequently in young people and less frequently as we age.

There are techniques to lessen hypnic jerks, such as cutting back on stimulants like caffeine or nicotine, avoiding physical activity right before bed, and getting enough magnesium. The hypnic jerks may also be lessened or eliminated by some medications. For instance, using low-dose clonazepam before going to sleep may eventually cause the hypnic jerks to go away.