We discuss some of them in detail below:. Neurocardiogenic syncope develops due to a short term malfunction of the autonomous nervous system ANS. Some people call it neurally mediated syncope NMS.
The ANS controls automatic body functions, including heart rate, digestion, and respiration rate. In NMS, a drop in blood pressure slows the heartbeat and pulse rate. Occupation, or situational, syncope is a type of neurocardiogenic syncope with physical rather than emotional, mental, or abstract triggers. Triggers include:. Orthostatic hypotension refers to fainting after standing up too quickly from a seated or horizontal position.
Gravity pulls blood into the legs, bringing down blood pressure elsewhere in the body. The nervous system usually reacts to this by increasing the heartbeat and narrowing the blood vessels.
This stabilizes blood pressure. However, if something undermines this stabilization process, there may be poor blood and oxygen supply to the brain, leading to fainting. Dehydration: If body fluid levels drop, so will blood pressure. This can make it harder for the blood pressure to stabilize. Therefore, less blood and oxygen reaches the brain.
Uncontrolled diabetes: A person with diabetes may need to urinate frequently, leading to dehydration. High blood sugar levels can damage certain nerves, especially those that regulate blood pressure.
Some medications: Taking diuretics, beta-blockers , and antihypertensive drugs may cause orthostatic hypotension in some people. Alcohol: Some people faint if they consume too much alcohol in a short amount of time. This may lead to orthostatic hypotension.
Carotid sinus syndrome: The carotid artery is the main artery that supplies blood to the brain. When there is pressure on the pressure sensors, or carotid sinus, in the carotid artery, it can cause fainting.
And, if one were actually hemorrhaging, or losing blood, the lying down, motionless posture would preserve blood and reduce further injury.
The process of going from standing or sitting to lying on the floor is actually one of the more dangerous aspects of fainting, though. Individuals may hit their head or other body parts on the way down, causing injury. The idea that fainting may be related to the potential for blood loss, rather than a response to needles themselves or a medical procedure in general, has been a topic of recent investigations. In one study of healthy people, watching a video of a blood draw led to slightly greater activation of the parasympathetic response than did watching a very similar video of an injection, suggesting there is something special about the blood itself.
This same research group has also shown that, if a person believes they are able to stop the procedure at any time, vasovagal symptoms can be minimized. Sign up today. Portsmouth Climate Festival — Portsmouth, Portsmouth.
Edition: Available editions United Kingdom. Become an author Sign up as a reader Sign in. If the person is unconscious, roll them on their side. Check they are breathing and that they have a pulse. If the fainting episode was brought on by heat, remove or loosen clothes, and try to cool the person down by wiping them with a wet cloth or fanning them. Assess the person for any potential injuries if they have fallen. In an emergency, always call triple zero for an ambulance if the person has not regained consciousness within a few seconds or recovered in a few minutes.
Hypotension and fainting Low blood pressure hypotension is a condition characterised by blood pressure that is lower than normal or usual for the person. Orthostatic hypotension Blood vessels respond to gravity by constricting tightening. Causes of orthostatic hypotension include: Nervous system diseases, such as neuropathy Prolonged bed rest Dehydration Irregular heartbeat heart arrhythmia Changes in blood pressure medication.
Where to get help Your doctor In an emergency, always call triple zero Fainting: first aid , Mayo Clinic. More information here. Low Blood Pressure , Medical Online. Give feedback about this page.
Was this page helpful? Yes No. View all blood and blood vessels. Related information. In those cases, a health care provider should assess it as soon as possible. One of the most common reasons people faint is in reaction to an emotional trigger. For example, the sight of blood, or extreme excitement, anxiety or fear, may cause some people to faint. This condition is called vasovagal syncope.
Vasovagal syncope happens when the part of your nervous system that controls your heart rate and blood pressure overreacts to an emotional trigger. Your heart rate slows, and your blood vessels widen.
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