Can a Seizure Cause You to Stop Breathing?

Seizures can absolutely cause you to stop breathing, and it happens more often than most people realize. When seizure activity spreads to certain brain regions, it can directly shut down the neural signals that drive each breath, producing what doctors call central apnea. Research has traced much of this effect to the amygdala, a small structure deep in the brain that, when activated by a seizure, can suppress breathing within seconds. This phenomenon is not just a curiosity of brain science; it is now considered a key factor in sudden unexpected death in epilepsy.

How Seizures Shut Down Breathing Through the Amygdala

For decades, it was unclear exactly how a seizure could halt breathing. The breakthrough came from monitoring patients in hospital epilepsy units, where researchers found that breathing stopped when seizure activity invaded the amygdala. In one landmark study, patients experienced central apnea and drops in blood oxygen when seizures spread to the amygdala. Strikingly, when researchers electrically stimulated the amygdala directly in the same patients, the apnea was reproduced, confirming a direct functional connection between the amygdala and the brainstem networks that control breathing.¹

Follow-up work pinpointed the timing. Breathing cessation began on average about 2.7 seconds after a seizure spread to the amygdala, which was far sooner than when seizures reached the hippocampus, another deep-brain structure commonly involved in seizures.² That speed is alarming because it means breathing can stop before a seizure has even fully generalized, while the person may still appear relatively calm on the surface.

Research in children has confirmed that this is not limited to adults. Electrical stimulation of the amygdala produced apnea in all eight pediatric subjects tested, ranging from 3 to 17 years old. The effect did not depend on what type of epilepsy the child had and was relatively specific to the amygdala: stimulating other nearby brain areas did not affect breathing. A machine-learning analysis of the stimulation data identified a focal subregion within the amygdala that consistently triggered apnea, which the researchers named the “amygdala inhibition of respiration” site.³

Perhaps the most unsettling finding from these studies is that patients had no idea they had stopped breathing. None reported feeling short of breath, and none woke up or became alarmed. The brain’s normal alarm system for suffocation appears to be overridden when the amygdala is seized, which means a person can be slowly losing oxygen without any subjective sense that anything is wrong.

How Severely Oxygen Levels Can Fall

The breathing disruption during a seizure is not always brief or mild. In a study of patients with focal epilepsy, blood oxygen saturation dropped below 90 percent in roughly a third of all seizures, whether or not those seizures spread to become full-body convulsions. About one in ten seizures caused drops below 80 percent, and around one in 25 fell below 70 percent. Carbon dioxide levels in the blood climbed in parallel, averaging a rise of about 19 mmHg from baseline, confirming that the oxygen loss was caused by not breathing enough rather than by some other mechanism.⁴

A separate analysis found that CO₂ levels reached or exceeded 50 mmHg in over a third of the seizures studied, and in a handful of cases exceeded 70 mmHg, which is well into dangerous territory. Oxygen levels dropped to 60 percent or lower in ten seizures, including five that never progressed to generalized convulsions.⁵ That last point is worth pausing on: you do not need to have a dramatic, full-body tonic-clonic seizure for breathing to become dangerously compromised. Even focal seizures that seem relatively contained can cause serious oxygen drops.

When respiratory monitoring was added to standard video-EEG evaluations, researchers found that apnea, whether from the brain failing to send breathing signals (central apnea) or from physical airway obstruction, occurred in about 31 percent of epileptic seizures observed.⁶ That figure makes it clear that seizure-related breathing disruption is common, not rare.

Breathing Problems That Continue After the Seizure Ends

The danger does not end when the seizure stops. The period immediately after a seizure, known as the postictal phase, brings its own set of respiratory risks. Many people fall into a deep, unresponsive state after a generalized seizure, and during that window, breathing can remain abnormal. Research has shown that when the brain’s electrical activity becomes broadly suppressed after a seizure, a pattern called postictal generalized EEG suppression, the associated breathing problems tend to be worse. Oxygen levels drop lower, CO₂ levels spike higher, and the CO₂ elevation lasts longer compared to seizures without that pattern of brain suppression.⁷

This postictal period is arguably when the risk is highest, because the person is often unconscious and unable to protect their own airway. If they are lying face down, their airway can become physically blocked by bedding or a pillow, compounding whatever central breathing suppression is already occurring. The combination of a brain that is not sending normal breathing signals and a body position that obstructs airflow is precisely the scenario that can turn a survivable seizure into a fatal one.

Why This Connects to Sudden Unexpected Death in Epilepsy

Sudden unexpected death in epilepsy, commonly called SUDEP, is the leading cause of death directly related to epilepsy, and the connection to breathing is now considered central to understanding it. For years, the assumption was that SUDEP was primarily a cardiac event, that a seizure triggered a lethal heart rhythm disturbance. But data from patients who died while being monitored in hospital epilepsy units has shifted that understanding. In most monitored SUDEP cases, death followed postictal central apnea rather than a primary cardiac arrest. The heart typically stopped after breathing had already ceased.⁸

Body position plays a documented role. A systematic analysis of over 250 SUDEP cases found that about 73 percent of those who died were found in the prone (face-down) position, a rate significantly higher than chance would predict.⁹ One detailed case report of a 35-year-old woman who died after a generalized seizure while prone concluded that asphyxia from the combination of postictal coma and positional airway obstruction was the likely cause, rather than a cardiac arrhythmia.¹⁰

The practical takeaway here is that many SUDEP cases appear to follow a cascade: a generalized seizure occurs, the person becomes deeply unconscious, breathing is suppressed by the seizure’s effect on the brainstem, the person ends up face down, and the combination proves fatal. This is not an inevitable sequence, and many of its links can be interrupted, a point that matters enormously for caregivers.

Serotonin and the Brain’s Breathing Safety Net

Why does the brain fail to restart breathing after some seizures but not others? Emerging research points to the serotonin system as a critical piece of the puzzle. Serotonin-producing neurons in the brainstem help drive the respiratory network and serve as part of the body’s backup system for restoring breathing when CO₂ levels rise. Dysfunction in this serotonin system has been identified in patients with drug-resistant epilepsy and has been linked to higher SUDEP risk.⁸

Animal studies have helped clarify what might be going wrong. In rats with chronic epilepsy, researchers found that serotonin wiring in key brainstem breathing centers was impaired. Interestingly, rats that did not experience severe postictal breathing shutdowns showed increased serotonin connections in those same areas, suggesting the extra wiring acted as a protective mechanism. Rats that did have severe breathing shutdowns, by contrast, showed decreased serotonin innervation despite the brain’s attempt to compensate by ramping up serotonin production at the molecular level.¹¹

This line of evidence also reveals an overlap with sudden infant death syndrome (SIDS). Both conditions appear to involve defects in serotonin-mediated CO₂ sensing and breathing autorescue, the brain’s ability to gasp and restart respiration when oxygen gets critically low. The overlap is not just theoretical; researchers have noted considerable parallels in the underlying pathology, which has fueled interest in whether serotonin-targeting drugs might eventually help reduce SUDEP risk.

When Sleep Apnea Complicates the Picture

Obstructive sleep apnea and epilepsy frequently coexist, and their interaction creates a vicious cycle that compounds the breathing risks described above. Sleep apnea causes repeated oxygen drops and sleep fragmentation during the night, both of which can increase the brain’s susceptibility to seizures. At the same time, seizures themselves can disrupt sleep architecture, potentially worsening existing sleep apnea. The two conditions appear to exacerbate each other through a positive feedback loop.¹²

The mechanisms driving this interaction include chronic intermittent low oxygen, inflammation in the brain, oxidative stress, and disruption of molecular signaling pathways.¹³ For someone who already has epilepsy, untreated sleep apnea may not only make seizures more frequent but also make each seizure’s impact on breathing more severe, because the brainstem respiratory centers are already under chronic stress from nightly oxygen deprivation.

If you or someone you care for has epilepsy and also snores heavily, experiences daytime sleepiness, or has been told they stop breathing in their sleep, screening for sleep apnea is worth pursuing. Treating the sleep apnea with CPAP or other interventions may improve seizure control in addition to the usual cardiovascular and quality-of-life benefits.

What Bystanders and Caregivers Can Do

Knowing that seizures can suppress breathing raises an obvious question: can anyone do anything about it in the moment? Evidence from hospital epilepsy monitoring units suggests yes. Nursing interventions such as repositioning the patient (especially rolling them off their face), suctioning the airway, and providing supplemental oxygen have been shown to reduce seizure duration, respiratory dysfunction, and brain suppression in the postictal period.¹⁴ These are simple, physical interventions, not advanced medical procedures, and they appear to make a real difference.

Outside the hospital, however, the biggest barrier is that most seizures happen unwitnessed, especially those occurring during sleep. This is where the fear that parents and caregivers describe becomes relevant. In qualitative research with parents of children with epilepsy, every parent expressed fear of missing a large seizure and not intervening in time. Some reported feeling the threat of losing their child during every seizure, and many described developing hypervigilant protective behaviors, like sleeping in the same room or checking on their child repeatedly during the night.¹⁵

The standard first-aid advice for seizures, keeping the person safe from injury, not putting anything in their mouth, timing the event, remains appropriate. But when the seizure ends and the person is unconscious, rolling them into the recovery position (on their side) so their airway stays clear is one of the most important things a bystander can do. Given that the vast majority of SUDEP cases involve people found face down, simply ensuring the person is not prone during the postictal period could plausibly prevent some deaths.

Genetic Factors That Bridge Heart and Brain Risk

Some people with epilepsy may carry genetic vulnerabilities that make both seizures and breathing or cardiac failure more likely. Research into a gene called KCNQ1 provides a striking example. Mutations in this gene are the most common cause of long QT syndrome, a heart rhythm disorder associated with fainting and sudden cardiac death. When researchers introduced these same mutations in mice, the animals developed epilepsy. It turned out that the KCNQ1 channel, previously thought to be only relevant to the heart, is also present in forebrain neural networks and brainstem nuclei that regulate both seizure activity and autonomic control of the heart.¹⁶

This finding suggests that in some patients, the same genetic defect that causes seizures also impairs the brainstem’s ability to maintain stable heart rhythm and breathing during and after a seizure. Sudden unexplained death accounts for a substantial portion of deaths in people with epilepsy, and shared ion channel mutations like this may explain why some individuals are at particularly high risk. It also highlights why cardiac screening may be valuable in certain epilepsy patients, especially those with a family history of unexplained sudden death or fainting.

When Seizure Treatments Themselves Affect Breathing

An ironic complication arises with vagus nerve stimulation (VNS), a device implanted in the chest that sends intermittent electrical pulses to the vagus nerve to reduce seizure frequency in people with drug-resistant epilepsy. While VNS can significantly improve seizure control, it can also disrupt breathing during sleep. In documented cases, patients developed sleep-disordered breathing tied to the VNS output. When clinicians reduced the stimulation intensity to help the breathing problems, seizure activity worsened, requiring a return to the original settings.¹⁷

This kind of tradeoff illustrates a broader tension in epilepsy management. The same neural pathways that control seizure activity are deeply entwined with those that regulate breathing and heart rhythm. Treatments that calm one system can inadvertently disturb another. For patients using VNS who report new snoring, daytime fatigue, or signs of sleep apnea after implantation, the device settings may need careful adjustment, a process that requires balancing seizure frequency against respiratory safety during sleep.