While often the cause of fainting is something minor, fainting also can be a sign of a serious underlying medical concern. Shamai Grossman, an associate professor of emergency medicine at Harvard Medical School, who has conducted 20 studies on fainting.
Fainting usually is caused by a temporary drop in blood pressure. During that brief drop, the brain does not get the blood flow that it needs—and you lose consciousness. One serious cause of this drop in blood pressure is bleeding, such as in the stomach or intestines, or from a rupture of the body's main artery, the aorta. Several different heart problems also can temporarily lower blood pressure.
One is heart block, in which the heart beats too slowly to pump enough blood. An irregular rhythm of the heart's main pumping chambers, the ventricles, can cause the heart to pump blood less efficiently. Abnormalities of a heart valve, particularly a stiffening of the aortic valve, also can cause a temporary loss in pressure. All of these heart problems often produce symptoms such as palpitations a feeling like your heart is skipping a beat or racing , shortness of breath, or chest tightness.
If you have any of these symptoms, it is urgent that you get to the hospital. Another serious cause of a sudden loss of consciousness is a seizure, which is an abnormality of the brain, not related to blood pressure.
Some seizures produce dramatic shaking movements and loss of consciousness for longer than most fainting spells. However, other seizures can be more subtle and hard to recognize as seizures. Sometimes fainting is caused by stimulation of the vagus nerve, which can briefly lower both heart rate and blood pressure. The condition is called vasovagal syncope SIN-cope-ee. It can occur if you strain while having a bowel movement or, for men, while passing urine , have blood drawn, get an injection, hear bad news, or even laugh too hard.
These kinds of fainting episodes commonly affect young people but can occur in older adults. Getting too hot or being in a crowded, poorly ventilated setting are common causes of fainting. Sometimes just standing for a very long time or getting up too fast after sitting or lying down can cause someone to faint. Emotional stress. Emotions like fright, pain, anxiety , or shock can cause blood pressure to drop. This is the reason why people faint when something frightens or horrifies them, like the sight of blood.
A person who is hyperventilating is taking fast breaths. Carbon dioxide CO2 levels in the blood falls, causing blood vessels to narrow. Blood flow to the brain decreases, making a person faint. Medical conditions. Conditions such as heart problems, anemia , low blood sugar , or postural orthostatic tachycardia syndrome POTS can cause fainting.
During pregnancy, the body undergoes a lot of changes, including changes in the circulatory system. These may cause a woman to faint. In turn, that causes your blood pressure to drop. When that happens, your body cannot deliver the blood your brain needs, and you lose consciousness. Because fainting is more likely when standing up, though, to prevent fainting, it can be useful for people prone to vasovagal syncope to lie down or sit down with their heads between their knees if they begin to feel lightheaded or dizzy.
Another kind of fainting can happen when you stand up from sitting or lying down, and your blood pressure drops quickly. This causes dizziness , lightheadedness or a brief loss of consciousness.
This is called orthostatic hypotension. Occasionally, a collapse may be caused by a more serious event such as a stroke or a disturbance in the normal heart rhythm. A faint might be telling you something is wrong and further examination is sometimes important. If a person complains of breathlessness, chest pains or heart palpitations, or if the pulse is faster or slower than expected, the person should see a doctor.
Similarly, slurred speech, facial droop or weakness in any limbs are signs of a serious problem. If possible, lie down and elevate the feet. This may prevent a loss of consciousness. Fresh air can also help, especially if you are feeling hot. If it is not possible to lie down, put your head down as low as possible. If you do faint, remain lying down for ten minutes. Sit up slowly when you need to get up.
Low blood pressure hypotension is a condition characterised by blood pressure that is lower than normal or usual for the person. Hypotension can be caused by a variety of factors including heart disease and abnormal heart rhythms, some infections, dehydration and medications for high blood pressure or certain heart conditions.
Frequent fainting spells or sensations of light-headedness need to be medically investigated to check for underlying causes. Blood vessels respond to gravity by constricting tightening. This increases or maintains blood pressure when we stand up from a sitting or lying position. For this reason, some people, particularly the elderly or those on blood pressure medication, should stand up from sitting or lying in bed slowly.
This helps prevent fainting after sudden changes in position.
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