The brain has multiple parts, including cerebellum, two hemispheres, and also brain stem. The brain needs blood flow to provide oxygen and glucose to the cells.
To keep your body in conscious state, an area known as the reticular activating system located in the brain stem need to be active, and at least one hemisphere of the brain must be in function.
Fainting occurs when either the both hemispheres of your brain or reticular activating system is deprived of blood, glucose, or glucose.
1. Reaction on Vagus Nerve
Fainting mostly triggered by the vagus nerve that make a connection between the brain and the digestive system. It also plays a role to manage the flowing of blood to the brain and also gut. When the vagus nerve is over stimulate, it starts to slow the heart rate and begin to lower blood pressure. This condition will reduce the blood supply that carried oxygen to the brain, then fainting is inevitably.
Stress, anxiety, panic, fear, and strong pain can stimulate the vagus nerve.
Anemia (lack of red blood cells) can cause fainting because your body don't have enough red blood cells to supply oxygen to your brain. Anemia is usually caused by lack of iron intake, disease or bleeding (eg excessive menstruation).
|What causes sudden fainting ?|
3. Changes in blood pressure
The changes in blood pressure may cause you to faint. Occasionally, your heart and blood vessels don't react fast enough when your body's oxygen needs is changing. It is very common in the elderly and in people who have certain health conditions, eg diabetes. Fainting can also happen when you stand up too long or work harder than what your body can handle.
Lack of fluid in the body (dehydration) can cause fainting also. Dehydration might be caused by diarrhea, vomiting, sweating, fever, hot weather or less drinking. Some health condition such as diabetes may also lead to dehydration because the patient usually frequently urinate. Diarrhea and vomiting, in particular, also can stimulates the vagus nerve. Therefore, they can also trigger fainting.
Drugs that are intended to control high blood pressure can work to strong to lower blood pressure causing fainting. Cocaine, marijuana, and alcohol also can cause fainting. Talk with your doctor if you think you often feeling faint and dizzy because of drugs you use.
Shock is a health problem, it is usually characterized by low blood pressure which can lead to fainting. Shock is a dangerous and emergency situation that usually comes from bleeding, but it can also come from a severe allergy (anaphylaxis) or severe infections. Shock victims usually looked confused at first, then they start losing consciousness when their condition worsened.
Shortage of blood sugar (hypoglycemia) can make you swoon. Hypoglycemia is not only caused by diabetes, but also because you does not eat in a long time.
Tip: What to do if you feel faint and dizzy?
Before fainting, you usually feel dizzy, the room seems spinning, cold sweats and nausea. You may also experience hearing whistling in your ear or blurred vision.
If you feel faint, lie down a little while. If you can not lie down, try to sit and squat down to put your head between your knees. This helps the blood flow to your brain. Just wait a few minutes until you start feeling better before you to stand. Now you can slowly stand up.