Waking up startled, often from hypnic jerks (sudden muscle twitches) or night terrors, is commonly caused by stress, fatigue, stimulants (caffeine/nicotine), or anxiety, making the brain easily overstimulated as you fall asleep or wake up; underlying issues like sleep apnea, trauma, certain meds, or sleep deprivation can also trigger these disruptive, involuntary awakenings.
There's a name for this phenomenon: It's called a hypnic jerk or sleep start. It's a sudden increase in muscle activity that happens to just about everybody and can be quite literally startling, though the intensity depends on the person, says Carl Bazil, MD Ph.
It has been suggested that the brain misinterprets muscle relaxation as falling, and so, stimulates muscle activity in response. Hypnic jerks usually occur during waking up or falling asleep. Patients will only notice these if they wake from their sleep and can describe the episodes as a 'jolt' or 'sudden falling'.
Stress, sleep disorders, chronic illness, underlying mental health conditions like ADHD or depression, relationship issues and diet often play a role. “One major reason people wake up with anxiety could be chronic stress and our bodies being in a constant state of fight or flight.
Nighttime panic attacks, also known as nocturnal panic attacks, can occur with no clear cause and awaken you from sleep. As with a daytime panic attack, you may sweat, have a rapid heart rate, tremble, be short of breath or breathe heavily.
In our study population, children with sleep terror had lower vi- tamin D levels than the control group. This suggests that chil- dren with sleep terror should be assessed in terms of vitamin D deficiency or insufficiency.
Finally, from a nutritional perspective, it has been suggested, albeit anecdotally, that deficiencies in magnesium, calcium and/or iron can also increase the chances of experiencing a spontaneous hypnic jerk.
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.
Hypnic jerks may just be a normal part of falling asleep but are either not noted or quickly forgotten. There are no known pathological causes. Indeed, the cause is unknown but may be the result of output from the brainstem reticular formation that becomes activated during the transition between wakefulness and sleep.
Sleep apnea warning signs include loud snoring, gasping or choking during sleep, pauses in breathing (noticed by a partner), excessive daytime sleepiness, morning headaches, irritability, and frequent nighttime urination, all stemming from disrupted, poor-quality sleep. These symptoms indicate breathing stops and starts, leading to fatigue and concentration issues during the day, so seeing a doctor is crucial for diagnosis and treatment.
Historically, an exaggerated startle reflex has been associated with a variety of psychopathological disorders including “combat neurosis” and posttraumatic stress disorder [PTSD].
What's going on? 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.
The 3-2-1 bedtime method is a simple sleep hygiene strategy: stop eating 3 hours before bed, stop working 2 hours before bed, and stop using screens (phones, tablets, TVs) 1 hour before sleep, helping your body transition to rest by reducing stimulants and digestive load for better sleep quality. A more detailed version adds 10 hours (no caffeine) and 0 (no snoozing) for a 10-3-2-1-0 rule.
Night terrors in adults usually point to an underlying mental health condition, like post-traumatic stress disorder or anxiety disorder.
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.
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.
Vitamin D deficiency can also play a role in causing muscle twitches. Your nerve cells need vitamin D to carry messages from your brain to your muscles, so it makes sense that without enough, your muscles would start to twitch and feel weak. You can get vitamin D from sun exposure.
Neurologic Diseases That Can Be Accompanied by Myoclonus
Children with sleep terror with frequent attacks had lower 25(OH) vitamin D levels than those without frequent attacks (p<0.001). Conclusion: This study demonstrated a greater prevalence of vitamin D deficiency or insufficiency among children with sleep terror.
Hypnic jerks, sleep starts, or hypnic myoclonia are a physiological, non-periodic, and abrupt myoclonic muscle contraction involving nearly all body muscles that occurs mainly on falling asleep. These physiological phenomena are experienced by up to 70% of the adult population sometime in their lives [1].
Foods including cheese, spicy foods, sugar and sweets (particularly chocolate), pizza, fast food, noodles or pasta, milk, and even meat have all been linked to nightmares. Drinks containing caffeine are also a major trigger for nightmares, including sports drinks, fizzy drinks, iced tea, and certain types of juice.
Here are 10 unexpected signs of a vitamin D deficiency that may surprise you.
Vitamins B
All B vitamins play a role in converting food into energy and best known for this is vitamin B12. Vitamin B12 deficiency can cause exhaustion and feelings of sadness or anxiety. As our metabolism is boosted by B vitamins, this can have a stimulating effect and cause sleep problems if taken late at night.