A violent coughing fit can make you black out for a few seconds, and doctors have recognised this since the 1800s.1PubMed. Cough syncope The faint usually comes from blood briefly failing to reach the brain, not from an electrical storm in it. The twitching that can come with this kind of faint looks so much like a seizure that it is often mistaken for epilepsy. The faint itself rarely harms you, but where it happens can, especially behind the wheel.2PubMed Central. Syncope: a complication of chronic cough
Fainting or Seizure, What Usually Happens
Doctors call fainting during coughing “cough syncope,” a term you may hear or see in your notes.3PubMed Central. Syncope: a complication of chronic cough Early doctors assumed it was a form of epilepsy, but by the mid-1900s it was understood as a pressure effect of coughing.4PubMed. Cough syncope Among 17 people with cough syncope, 12 had completely normal brainwave tests (EEGs) between episodes.5PubMed. EEG in cough syncope During recorded episodes, the EEG showed the general slowing seen in any faint.6PubMed. EEG in cough syncope Eight of those people had rhythmic or jerking movements during the faint, yet none showed seizure activity.7PubMed. EEG in cough syncope
To a witness, the episode usually starts with a run of hard coughs, often several in a row without a good breath. The person may say they feel lightheaded, or look dim or grey, just before they go down. The blackout itself lasts only seconds, and they tend to come round quickly and know where they are.
Any brain briefly short of blood can make the limbs jerk, which is why witnesses assume a seizure. A quick recovery points toward a faint and long confusion afterwards more toward a seizure, though neither is a dependable test on its own.
If you saw it happen, a few details help the doctor: how long the coughing went on before the blackout, how long the person was out, whether there was jerking and for how long, and how quickly they were back to normal.
Why Hard Coughing Makes You Pass Out
Each hard cough sharply raises the pressure inside the chest.8PubMed Central. A case of cough syncope diagnosed by the Valsalva maneuver and cough induction test under invasive arterial pressure measurement Less blood then returns to the heart, and the heart pumps out less.9PubMed Central. A case of cough syncope diagnosed by the Valsalva maneuver and cough induction test under invasive arterial pressure measurement The pressure also passes into the fluid around the brain and raises pressure inside the skull.10MedLink Neurology. Cough syncope Blood can be pushed out of the head, sometimes stopping brain blood flow for a moment.11MedLink Neurology. Cough syncope
A cough is a forceful push against a closed throat, so the pressure spikes sharply. A run of coughs repeats that spike with no break, and the brain goes short of blood within seconds. Once the coughing stops, blood flows back and the person wakes.
That is why a single cough rarely does it. One cough raises pressure only for an instant, and the body recovers before anything happens. Fainting usually needs a long, violent fit, which is why people with chronic hard coughs are most at risk.
Because the person goes down, the body ends up flat, which makes it easier for blood to reach the brain again. That, plus the end of the coughing, is why waking up is so fast.
A nerve reflex can make things worse. People who faint from coughing have a much bigger blood pressure drop with coughing than other people who faint.12PubMed. Effect of cough on heart rate and blood pressure in patients with “cough syncope” In them, the cough sets off a reflex that wrongly lowers blood pressure, much like a common faint.13PubMed. Effect of cough on heart rate and blood pressure in patients with “cough syncope” In one reported case, a drug that blocks this reflex stopped the faints.14PubMed Central. Malignant Cough Syncope from Idiopathic Vagal Inflammation
Who Is Most Likely to Faint From Coughing
More than 95% of cases are men, typically in their 50s.15MedLink Neurology. Cough syncope Many are muscular or overweight, and many smoke now or did in the past.16MedLink Neurology. Cough syncope A bigger chest can create the very high pressures behind the faint.17PubMed. Cough syncope Most have a chronic cough, severe coughing bouts, and lung disease that narrows the airways, such as COPD.18MedLink Neurology. Cough syncope About 1 in 10 people with a chronic cough develop this kind of fainting, almost all of them men.19PubMed Central. Chronic cough: new insights and future prospects Narrowed airways matter because each cough takes more effort to move air out, producing bigger pressure spikes in the chest.
Other triggers exist. Chest infections and postnasal drip can cause it even in non-smokers.20MedLink Neurology. Cough syncope Asthma is common among people who faint from coughing.21PubMed Central. Clinical features of cough syncope: a systematic review Some blood pressure pills called ACE inhibitors cause a dry, persistent cough; one man’s coughing blackouts stopped after his pill was switched.22Cukurova Medical Journal. Cough Syncope due to ACE Inhibitor ACE inhibitor names often end in “-pril,” like lisinopril or ramipril. Don’t stop a blood pressure pill on your own, but do ask your doctor whether a different pill would avoid the cough.
In children, severe coughing from whooping cough can cause brief faints.23Annals of Emergency Medicine. Syncope and Breath Holding in Children A child who faints during whooping cough needs urgent care.
The typical profile is not the only one: a woman or a slim person with a severe cough can still faint, and any blackout needs a doctor’s check to rule out other causes.
Why Cough Fainting Can Be Dangerous
Driving is the main danger. Cough syncope can be fatal if it happens while driving.24PubMed Central. Syncope: a complication of chronic cough Six serious car crashes have been blamed on drivers blacking out from coughing.25PubMed. Cough syncope as a cause of motor vehicle crash: fatal distraction? The warning of lightheadedness may last only a second or two, which is too short to stop safely, and a car travels a long way in those seconds.
In the UK, car drivers must stop driving and tell the licensing agency, for 6 months after one episode or 12 months after more than one within 5 years.26Medical Fitness to Drive Consultancy. Cough Syncope and Driving (DVLA): Group 1 & 2 Fitness to Drive Bus and lorry drivers face 12 months after one episode and 5 years after repeated ones.27Medical Fitness to Drive Consultancy. Cough Syncope and Driving (DVLA): Group 1 & 2 Fitness to Drive Losing a licence can hurt people who drive for work.28PubMed Central. Chronic cough: new insights and future prospects
If you have blacked out, get medical advice before driving again. Telling the licensing agency is a legal duty for the driver, not something the doctor does automatically. Rules elsewhere differ, so check your local licensing agency. If a hard fit builds while you are driving, pull over safely as soon as it starts, and don’t try to drive through it.
At home, the usual harm is a head injury from falling. Sit or kneel down when a hard fit starts, and keep cough medicine handy if your doctor recommends it.
How Doctors Check a Coughing Blackout
There are no agreed official guidelines on how to test for it.29PubMed Central. Syncope: a complication of chronic cough Much rests on your history. A tilt-table test holds you upright on a tilting bed while blood pressure and heart rate are tracked.30PubMed Central. Diagnostic role of head-up tilt test in patients with cough syncope Coughing during the test brought on warning symptoms in about half of people and a full faint in 7%.31PubMed Central. Diagnostic role of head-up tilt test in patients with cough syncope The tilt test helps most when the story alone isn’t clear.32PubMed Central. Diagnostic role of head-up tilt test in patients with cough syncope A brainwave test helps rule out epilepsy.
The doctor’s questions have a purpose. They will ask whether the blackout came during or just after the coughing, since that timing is the main clue to a cough-triggered faint. They will ask about warning feelings, because a faint usually gives a brief warning, and about how you were afterwards, since a quick return to normal points toward a faint.
A doctor will usually also check your blood pressure and heart rhythm, because heart problems can cause blackouts and must be ruled out. A heart tracing is a simple, painless test that records the heart’s electrical activity. If headaches come with coughing or the story suggests a brain cause, the doctor may arrange brain imaging.
To prepare, bring a witness’s description or a phone video, and list all your medicines, including blood pressure pills. Be ready to describe how often and how hard you cough, and mention any headaches that come with coughing.
Treating the Cough Stops the Fainting
Treatment aims to stop the cough that triggers the faint.33PubMed Central. Cough syncope induced by post nasal drip successfully managed by Gabapentin Inhalers that open the airways, cough medicines, and treatment of the underlying lung problem are used.34MedLink Neurology. Cough syncope The fainting usually improves or stops once the cough is treated, without seizure medication.35MedLink Neurology. Cough syncope When acid reflux is behind the cough, treating it generally lets people return to normal life.36MedLink Neurology. Cough syncope Seizure medicines aren’t used because the faint is not caused by abnormal electrical activity in the brain.
The right fix depends on the cause. Quitting smoking reduces a chronic cough over time. Postnasal drip can be treated with nasal sprays, and reflux with diet changes and acid medicines. Better asthma control reduces coughing fits.
Inhalers make it easier to move air, so each cough needs less force. They help mainly when the cough comes from asthma or COPD, and they work best used as prescribed.
When Coughing Leads to a Real Seizure or Brain Problem
Two men first told they had cough fainting turned out to have epilepsy.37Default. Is it Peri-ictal Cough or Cough-related Syncope? Their attacks began with coughing, then stiffening, loss of consciousness and jerking for 1–2 minutes.38Default. Is it Peri-ictal Cough or Cough-related Syncope? One had confusion for about an hour afterwards.39Default. Is it Peri-ictal Cough or Cough-related Syncope? In a few people the cough is not the cause of the faint but the first sign of a seizure starting in the brain. Stiffening and longer jerking suggest a seizure rather than a simple faint. A brainwave test between episodes is more likely to show abnormal activity in these people, though a normal test does not rule epilepsy out.
Chiari malformation is a condition where the lower brain sits low into the spinal canal. Its main symptom in adults is headache at the back of the head, often worse with coughing or laughing.40PubMed Central. Unusual Etiology of Chronic Cough and Syncope as Chiari Malformation Type 1 Fainting is a rare sign of it.41PubMed Central. Cough Syncope, a Rare Presenting Symptom of Chiari I Malformation and Atlanto-Occipital Assimilation The low-sitting part of the brain can block the flow of fluid around the brain and spinal cord. A cough raises pressure in the head, which can briefly worsen that blockage and cause a sudden headache. Surgery helped headaches in some patients.42PubMed. Headache associated with the Chiari type I malformation An MRI scan of the head is how doctors check for it.
Some signs point away from a simple faint: jerking lasting a minute or more, long confusion afterwards, tongue biting or wetting yourself, and headaches triggered by coughing. Any of these calls for a neurologist.
Other Everyday Triggers of Fainting
Cough fainting is one of several faints triggered by specific situations.43SAGE Journals (Journal of Child Neurology). Research Progress on Situational Syncope In adults, faints while urinating or passing stools are more common.44SAGE Journals (Journal of Child Neurology). Research Progress on Situational Syncope In children, standing still for long periods is a common trigger.45SAGE Journals (Journal of Child Neurology). Research Progress on Situational Syncope
Straining to pass a stool involves holding the breath and bearing down, which raises chest pressure much like coughing does. Urinating faints often happen when getting up at night, when blood pressure can drop on standing.