Your girlfriend likely experiences hypnic jerks (or "sleep starts"), common, harmless muscle twitches as she falls asleep, caused by the brain misinterpreting relaxation as falling, often triggered by stress, caffeine, or exhaustion, but can be managed with good sleep hygiene. While usually normal, frequent or disruptive twitching might warrant a doctor's advice to rule out other factors, say Sleep Foundation, Medical News Today, Calm, WebMD, National Institute of Neurological Disorders and Stroke.
This body movement is what doctors and scientists call a hypnic (or hypnagogic) or myoclonic jerk. It's also known as a "sleep start," and it can literally startle you out of falling asleep. This type of feeling is normal, and it can happen before people enter the deeper stages of sleep.
Sleep twitches are normal and usually harmless. Prioritize sufficient sleep, aim for 7-8 hours nightly, and establish a relaxing bedtime routine, avoiding late-night food, caffeine, and smoking.
Physiologic myoclonus, which happens in otherwise healthy people and doesn't need medical treatment. Some examples are hiccups and the jerks (or “sleep starts”) that some people have while drifting off to sleep. Pathologic myoclonus, which happens because of an underlying disorder of the brain or nerves.
Here we review evidence that myoclonic twitches—brief and discrete contractions of the muscles, occurring exclusively during REM (or active) sleep, that result in jerks of the limbs—help animals map their ever-changing bodies by activating skeletal muscles to produce corresponding sensory feedback, or reafference.
Myoclonus may occur normally (for example, jerking of a leg when a person is falling asleep), but it may result from a disorder, such as liver failure, a head injury, low blood sugar, or Parkinson disease or from use of certain medications.
Early ALS twitches (fasciculations) feel like brief, sporadic, annoying muscle spasms, similar to an eye twitch but in limbs, back, or stomach, often visible or felt under the skin, usually not painful initially but can become persistent and interfere with sleep, often accompanied by subtle weakness or stiffness, rather than intense pain. They're like tiny ripples or quivers, often happening when muscles are at rest, but differ from benign twitching by eventually leading to noticeable weakness and atrophy in the affected muscles.
The American Academy of Sleep Medicine (AASM) identifies a variety of potential causes for hypnic jerks, including anxiety, stimulants such as caffeine and nicotine, stress, and engaging in strenuous activities during the evening. Additionally, fatigue or sleep deprivation may contribute to their occurrence.
Nervous system conditions that can cause muscle twitching include:
Calcium and Magnesium
A calcium imbalance occurs when you have a magnesium deficiency and a too-high calcium-to-magnesium ratio. Studies suggest that magnesium deficiencies cause twitches and spasms when calcium becomes too high and overstimulates nerves.
These are completely normal and aren't the same as a myoclonic seizure. They are: Hypnic jerks: If you've ever had a sudden muscle twitch or spasm right as you were falling asleep, that was a hypnic jerk (the name comes from “hypnos,” the Greek word for “sleep”).
Healthcare providers diagnose periodic limb movements of sleep (PLMS) based on your medical history and the results of an overnight sleep study (polysomnogram).
The most common substance type associated with hypnic jerks is stimulants. This includes cocaine and methamphetamine. Because of the way that stimulants speed up the body, and can also cause muscle twinges even when awake, taking stimulants can lead to a higher chance of hypnic jerks.
Hypnic jerks may be exacerbated during stressful conditions occurring during a normal part of sleep onset [4]. These stressful conditions that may trigger hypnic jerks include fatigue, stress, sleep deprivation, vigorous exercise, and stimulants like caffeine and nicotine [5].
Twitches are common and very rarely a sign of anything serious. They often go away on their own, but see a GP if a twitch lasts more than 2 weeks.
The truth is that myoclonus occurs in nearly everyone, not just those with anxiety, and so it may not even be anxiety related at all. Some people twitch when they start to fall asleep at night. Others twitch after exercise.
Tourette syndrome (TS) is a condition of the nervous system. TS causes people to have "tics". Tics are sudden twitches, movements, or sounds that people do repeatedly. People who have tics cannot stop their body from doing these things.
There are three major types of skeletal muscle fibers. These are called fast twitch, slow twitch and intermediate. Generally, fast twitch fibers generate high force for brief periods of time. Slow twitch fibers generate lower amounts of force but can do so for longer periods of time.
Muscle spasms (also known as tremors) are also a common early sign of MS, which can feel like mild flutters or more like uncontrollable jerking movements. This symptom is often accompanied by muscle cramps and stiffness throughout the legs and back.
What does sleep anxiety feel like?
These are common symptoms of anxiety. Muscle twitches can be slow, sporadic, intermittent, or involve muscle tremors. They can last for seconds or even hours and can affect any part of the body, such as the arms, legs, facial muscles, abdominal muscles, and neck.
A muscle twitch is a short contraction that sometimes occurs repeatedly − think eye twitching. Such movement can be uncomfortable and inconvenient, but it isn't usually painful. Muscle spasms, on the other hand, are prolonged muscle contractions that are often painful.
Early signs of ALS often involve painless muscle weakness, such as tripping or dropping things, along with muscle twitching (fasciculations), cramping, and stiffness (spasticity), commonly starting in limbs but sometimes affecting speech (slurring) or swallowing (choking). Other early indicators include significant fatigue, poor balance, or even uncontrollable laughing/crying (pseudobulbar affect). These symptoms usually begin subtly in one area and spread, affecting daily activities before becoming severe.
ALS is 20% more common in men than women. However, with increasing age, the incidence of ALS is more equal between men and women. About 90% of ALS cases occur without any known family history or genetic cause. The remaining 10% of ALS cases are inherited through a mutated gene with a known connection to the disease.
The first signs of Motor Neurone Disease (MND) often involve muscle weakness, leading to stumbling, a weak grip, or difficulty lifting objects, but can also start with speech/swallowing issues (slurring, choking) or muscle twitching (fasciculations) and cramps. These symptoms are usually mild and painless initially, varying by where the motor neurons are first affected, but often include fatigue and affect limbs or speech/swallowing muscles.