Why do I keep fainting? When it may be serious, and how the heart can be a factor

Should people who feel faint sit with their heads between their knees? How can you tell whether someone who has fainted should go to a hospital accident and emergency department – or even see a cardiologist? Dr Elijah Behr, a cardiologist at Mayo Clinic Healthcare in London, explains five things to know about fainting. Fainting or blacking out, also known as syncope, is a temporary loss of consciousness because of insufficient blood flow to the brain. 1. Different types of fainting Vasovagal syncope is the medical term for the most benign kind of fainting, simple fainting without a serious underlying cause, Behr explains. This type of fainting is common. “In some people, if they have a drop in blood pressure from emotional distress, pain, illness or dehydration, for example, or just generally have low blood pressure, any provocation causes a reflex in the heart,” Behr says. “Rather than the heart speeding up and pumping more forcefully to maintain the blood pressure, it starts to slow down. The blood pressure drops, the heart rate slows further and the heart can pause for many seconds; sometimes close to a minute for some people who have more severe fainting episodes.” Usually with this type of fainting, the person falls to the floor, blood pressure returns to the brain and the person starts to recover. However, if someone faints in a vulnerable location or position, it can be dangerous to that person and others, Behr notes. The syncope that most concerns healthcare professionals is cardiac syncope, blacking out because of an underlying heart disease such as a heart rhythm abnormality or arrhythmia, he explains. “This is usually a more abrupt loss and return of consciousness than in simple fainting. If you’re older, you’re more likely to have underlying heart disease that you may or may not be aware of. That’s one of the reasons to be more concerned about loss of consciousness in older individuals,” Behr says. “Young people can also have heart diseases that can cause cardiac syncope that may be a warning sign of something more serious to come, so it is important to investigate it.” Others for whom a blackout can be a warning sign of a serious heart problem include people with a family history of inherited heart problems, unexplained deaths or premature sudden deaths; people whose fainting is related to exercise; and people whose fainting is associated with heart palpitations or the heart feeling like it is racing away, he adds. 2. Signs that you should sit or lie down “There will be a sensation of lightheadedness. There may be a sensation of nausea or buzzing or ringing in the ears,” Behr says. “Some people describe tunnel vision – their vision closing in on them before they actually pass out – and some may actually lose vision but still be aware, not lose consciousness completely, and then recover. Other typical signs include feeling sweaty and clammy.” Some people get about a half an hour of warning before fainting; some people may get 30 seconds, he adds. 3. What to do if you or someone else faints: Check that the person is breathing and has a pulse. If not, call for emergency help, and, if you know how, initiate cardiopulmonary resuscitation. If the person is breathing and has a pulse, ensure they are lying flat, and their airway is open using the recovery position and call for help. If you feel like a faint may be coming on, position your head lower than your heart: for example, between the knees. Rest after coming out of the faint. Drink water after the faint, adding electrolytes if you have them. “If your blood pressure is getting low and you’re getting those symptoms, it means the blood doesn’t get into your brain, and if your heart is trying to push the blood to your brain against gravity, then it’s struggling. “You really need to get your head level or below your heart so the blood pressure gets back to the brain, and that will avert all the symptoms and the vicious cycle that ensues,” Behr advises. “Get your head between your knees or lie down and put your head down and your feet up in the air, depending on where you are and what is feasible to do.” Getting up and walking around straight away is probably the worst thing to do, he warns. “Your blood pressure will drop further, and you’ll feel worse, and collapse and fall and injure yourself,” he says. “The best thing is to stay where you are and get flat, and when you’re feeling better, drink some water, maybe with some electrolytes if you’re dehydrated. “For general preventive measures, we advise most people who have fainted to drink more water and to sometimes add a bit of salt to their food, because generally they’re running a low blood pressure.” Sometimes, getting hydrated and adding salt to the diet may not be enough. Occasionally, people need to take medications to improve blood pressure control and increase blood pressure to prevent fainting episodes, Behr says. 4. When to seek medical help If someone has had a simple fainting spell, it is best to talk to a doctor. “Particularly if it’s a first onset of symptoms, it’s best not to ignore it,” Behr says. “Often people go to the emergency department after a first faint, which I think is very fair to do and I would encourage.” If someone has had simple faints before, the circumstances that bring them on are typical for them and a doctor has evaluated them before, they may not need to go to the emergency department every time, he adds. The more concerning situations are older people having faints where other conditions may be having an effect; people who are having recurrent faints despite keeping well hydrated; if there has been an injury because of a faint; and if the blackout comes on abruptly and with other signs that there may be an underlying cardiac condition. “We need to make sure that they are treated and that something else isn’t being missed,” Behr says. Sometimes faints can look like seizures, he adds. “Differentiating a seizure and epilepsy from fainting requires involvement of a cardiologist and neurologist.” 5. Overcoming faintness at the sight of blood It is very common to feel faint at the sight of blood, Behr says, but cognitive behavioural therapy (CBT) may help. Working with a mental health counsellor such as a psychotherapist, you become aware of inaccurate or negative thinking, to be able to view challenging situations more clearly and respond more effectively. Like what you read? 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Why do I keep fainting? When it may be serious, and how the heart can be a factor

Fainting takes different forms, a heart doctor says; a drop in blood pressure can cause it – or it can be a sign of a serious condition

1. Different types of fainting