When Satyajit Thakur, a Hong Kong-based financial analyst, was in his mid-20s, he started experiencing episodes where he was jolted out of his sleep by sudden, jerky movements coursing through his body. It was disconcerting, as he did not know the reason behind these twitches. Satyajit was eventually diagnosed with hypnic jerks based on his symptoms.
“It usually occurred when I was tired, stressed out or awake late at night. I would just nod off on the couch watching television, and there would be a sudden jerk on my hand or leg, waking me up,” says the 40-year-old. The jolt was usually accompanied by a falling sensation. “Mostly, I would just go back to sleep, but sometimes my sleep would get disturbed,” he added.
Satyajit had an erratic lifestyle because of work; he often slept late, ate at odd hours and didn’t follow a healthy lifestyle. “As I grew older, I consciously led a more disciplined life, focusing on good sleep hygiene, eating properly and doing regular exercise. This helped bring down the episodes, and now I rarely get hypnic jerks,” he adds.
What are hypnic jerks?
Hypnic jerks, also called hypnagogic jerks or sleep starts, are sudden, involuntary movements of the neck, hands, legs and sometimes the whole body resulting from muscle contractions. This usually occurs when an individual is in a state between wakefulness and sleep.
According to the National Institute of Neurological Disorders and Stroke (NINDS), hypnic jerks are a type of ‘myoclonus’ — sudden jerks or twitches that cannot be controlled. In some individuals, the jerks are accompanied by a feeling of falling, an electric shock-like sensation, loud noises or vivid dreams. Another type of commonly occurring myoclonus is hiccups.
What causes hypnic jerks?
While the exact cause of hypnic jerks remains uncertain, researchers and medical experts suggest they could be linked to signals originating from the brain or spinal cord.
“Hypnic jerks occur when a part of the brain is still active while the other parts are in the process of shutting down as one falls asleep, causing the muscles to relax. The nerves in the brainstem misunderstand the signals and respond by causing muscle contractions that feel like sudden jerks or twitches,” says Dr Anil R, consultant neurologist, Manipal Hospital, Bangalore.
Most hypnic jerks are benign, meaning they are mild and do not have an adverse impact on health. “They are the body’s response to tiredness, stress or lack of sleep. The symptoms usually improve with rest and relaxation,” adds Dr Anil.
In some instances, certain nutritional deficiencies like low sodium, calcium or magnesium can also cause myoclonic jerks.
“However, if the jolts are recurrent, accompanied by disorientation and confusion, or if the affected individual drops objects [after waking up following a jerk] or has a fall immediately after getting up, it could indicate a serious brain or nerve condition,” adds Dr Anil.
Also, if a hypnic jerk is followed by repeated vomiting, low concentration and drowsiness, it is advisable to consult a physician.
Risk factors for hypnic jerks
According to experts, the risk factors for hypnic jerks include:
- Sleep deprivation
- Fatigue
- Anxiety and stress
- Overconsumption of caffeine, especially close to bedtime
- Vigorous exercise in the evening or night
- Alcohol or nicotine abuse
Effects of hypnic jerks
Occurring in around 60–70 percent of the population, the effects of hypnic jerk can vary depending on the individual. Most people just sleep through the episodes. However, the jerks are sometimes frequent and strong enough to disrupt sleep and cause insomnia. Sleep deprivation, combined with fatigue and stress, can in turn cause complications like sleep terrors and sleepwalking.
“For some people, sleeping in an uncomfortable position, taking medication such as methadone, morphine and escitalopram or physical conditions like Parkinson’s disease, migraines and brainstem lesions can trigger these jerks,” says Dr Ashish Dhotre, consultant, respiratory medicine, Noble Hospital, Pune.
A research article published in the journal Handbook of Clinical Neurology, describes hypnic jerks as being abrupt and occasionally followed by rapid heartbeat, sweating and irregular breathing. The researchers found that these attacks had a frequency of more than one per night. They lasted for some weeks or even months and occurred in all stages of sleep, including the onset of sleep and during the light and REM (rapid eye movement) stages of sleep.
Diagnosis and treatment
Experts say when an individual presents with hypnic jerks that are interfering with sleep or causing insomnia, determining the cause is important.
“We advise blood tests to rule out sodium, calcium or magnesium deficiency. If there is a deficiency, supplements may be given to treat the problem. A CT scan of the brain and a nerve conduction study may be suggested to check for any other serious condition,” says Dr Anil.
He adds, “In some people, tests may be conducted to rule out myoclonic epilepsy, characterized by seizures in the form of short, jerky movements that are different from hypnic jerks. Based on the diagnosis, medications may be prescribed to treat the condition.”
How to prevent hypnic jerks?
Experts suggest the following methods to prevent hypnagogic jerks or sleep starts:
- Follow a regular sleep and wake-up schedule every day.
- Ensure a calm and relaxing environment during bedtime.
- Stop engaging with electronic devices at least an hour before going to bed.
- Engage in activities that help you calm down, like having a warm bath, listening to soothing music or reading a book.
- Maintain a regular fitness regimen, but avoid rigorous physical activity closer to bedtime.
- Take up meditation, yoga and breathing exercises to combat stress.
- Avoid smoking and minimize alcohol intake.
- Regulate caffeine intake; avoid caffeine in the evening and at night.
- Ensure adequate hydration.
Takeaways
- Hypnic jerks, also called hypnagogic jerks or sleep starts, refer to sudden, involuntary muscle twitches or contractions that usually occur as a person falls asleep. The condition occurs in around 60–70 percent of the population.
- Risk factors of hypnic jerks include fatigue, sleep deprivation, stress and alcohol or nicotine abuse.
- The effects of hypnic jerks might vary depending on the individual. Most people just sleep through the episodes. However, if the jerks interfere with sleep or cause repeated vomiting, low concentration and drowsiness, it is advisable to consult a physician.
- Measures like following a regular sleep-wake cycle, ensuring a calm environment during bedtime and avoiding smoking can help prevent the condition.
