Mystery of sleep spasms

YOU'RE just about to drift off when—bam!—your body jerks awake as if you just fell off a cliff. It's jarring, sometimes even alarming, but completely normal. These sudden, involuntary muscle twitches, known as sleep spasms or hypnic jerks, happen to a lot of people.

- DARSHITA JAIN

"These are common and seen in around 60–70% of individuals. They occur very randomly and can affect people of all ages," says Dr Y Muralidhar Reddy, senior consultant and head, department of neurology at Renova Century Hospitals, Banjara Hills. Most of the time, they're harmless, but they can be unsettling—especially if they occur frequently.

The exact cause of sleep spasms isn't always clear. However, certain factors can increase the likelihood of experiencing them. Some people even describe a sensation of falling, an electric shock, or brief hallucinations right before they happen.

"Most do not have an identifiable cause. They can be triggered by extreme tiredness, sleep deprivation, stress and anxiety, and excessive consumption of brain stimulants such as caffeine and nicotine," Dr Reddy explains.

For most, these twitches are nothing more than an occasional annoyance. But for some, they can be intense enough to wake them up multiple times a night.