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  • Writer's pictureMatthew Corbin D.C

What are night Zaps? A Hypnic Jerk Overview

An image of a man experiencing a hypnic jerk
Night Zap

Hands up if you've ever had the sensation that you are falling, just as you are going to sleep? ✋️. What about an electric shock sensation, or a quick panic sensation with a sudden deep breath? Or think something is wrong with your heart? Do not worry, I'm here to explain this weird sensation to put your mind at rest!

What are hypnic jerks?

Hypnic jerks, also known as sleep starts or hypnagogic jerks, are sudden, brief, and involuntary muscle contractions that occur as a person is falling asleep. These phenomena are a common part of the human sleep process, often described as feeling like a falling sensation or an electric shock. They can cause a person to awaken suddenly for a moment and are often accompanied by a rapid heartbeat, quickened breathing, sweat, and sometimes a vivid dream or sensory experience. Some have even reported a bang or explosion sensation in the head. They can be scary, mine started as a young teenager. And at the time there was no information on this subject. I went to the doctors and they just said it's nothing to worry about. Easier said than done! I still get them, but they don't worry me anymore. My first hypnic jerks started in my head, a fuzzy, Zappy sensation where I'd have to shake my head for it to go away. Then they went to my chest. That was more of a falling sensation that made my heart beat faster. If they happen now, I know what it is and fall back to sleep no problem.

Sleep Starter

What causes a Hypnic Jerk?Mechanisms and Physiology:

The exact cause of hypnic jerks is not fully understood, but they are believed to be a natural part of the sleeping process. Researchers suggest that they may result from the natural downshifting of the nervous system as it transitions from wakefulness to sleep. During this transition, the body undergoes various physiological changes, including a decrease in temperature, heart rate, and breathing rate. One theory is that hypnic jerks occur when nerves "misfire" during the transition, leading to a temporary arousal that results in the muscle twitch. Another hypothesis is that as the muscles relax, the brain misinterprets the relaxation as a sign of falling and reacts by sending signals to the muscles to tense up, hence the jerking motion.

Signs and Symptoms:

The primary symptom of a hypnic jerk is the sudden jerk or twitch of the body, often leading to arousal from sleep. This can be accompanied by:

- A falling sensation

- A flash of light or a dream, which can be vivid or startling

- Rapid heartbeat

- Quickened breathing

- Perspiration

An electrical type sensation of a hypnic Jerk

Is a hypnic jerk serious? Who Does It Affect?

Hypnic jerks are common and can affect people of all ages, including infants and the elderly. They are not considered harmful and do not indicate a sleep disorder or health condition. Most people will experience them at some point, though the frequency and intensity can vary widely from person to person.

Is There Any Health-Related Issues?

While hypnic jerks themselves are not harmful, frequent and severe jerks can disrupt sleep patterns and lead to or exacerbate sleep-related issues such as insomnia. Stress, anxiety, caffeine consumption, physical activity close to bedtime, and certain medications can increase the frequency or intensity of hypnic jerks. Reducing these risk factors can help minimize occurrences.

Preventive Measures and Management:

An image of a man sleeping peacefully

To reduce the likelihood of experiencing hypnic jerks, consider adopting good sleep hygiene practices:

- Maintain a regular sleep schedule.

- Create a comfortable, sleep-conducive environment.

- Limit caffeine and heavy meals close to bedtime.

- Avoid intense physical or mentally stimulating activities before sleep.

- Practice relaxation techniques, such as meditation or deep breathing, to reduce stress and anxiety.

In Summery

Hypnic jerks are a common, typically harmless part of the sleep process. While their exact cause remains partly a mystery, understanding their nature and potential triggers can help manage their occurrence. Adopting a healthy sleep routine and managing stress levels can significantly reduce their frequency and ensure a better night's sleep.

A man waking up in the morning well rested and happy


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