Fainting after an orgasm can be scary. In most cases, it is not the orgasm itself that causes a person to faint, but the circumstances surrounding it. Low blood sugar, intense sex, fatigue, and even anxiety may trigger fainting. People who pass out after an orgasm usually do not need to worry.
Vasovagal syncope is the most common type of fainting. It happens when a person’s blood pressure suddenly drops, temporarily depriving the brain of oxygen, and it results in the person falling unconscious.
It occurs when the vagus nerve, which regulates heart rate and blood vessel constriction temporarily loses normal regulation due to overstimulation. As a result, the blood vessels widen, blood pressure drops, and the person faints.
Hyperventilation during an orgasm or intense sexual activity can reduce the amount of oxygen flowing to the brain, which may cause a person to faint.
People who feel anxious about sex may also hyperventilate during an orgasm or shortly afterward. Once a person’s breathing returns to normal, the risk of fainting passes.
Hunger and thirst
Sometimes, sex or masturbation can temporarily distract a person from other physical needs, such as water and food. Intense sexual activity is a lot like aerobic exercise, also increasing a person’s need for water and oxygen. So, if a person does not drink enough water, they can become dehydrated and even pass out.
Sexual pleasure may likewise distract a person from their hunger. Low blood sugar can cause fainting. The risk of fainting is higher in people with certain medical conditions, including those with diabetes on blood glucose-lowering medications.
Stress and anxiety
While an orgasm itself might be pleasurable, the sensations surrounding it might not be. Some people feel anxious or ashamed about sex.
Anxiety and stress can cause fainting in several ways. A person might hyperventilate, depriving the brain of oxygen. Anxiety may also cause vasovagal syncope, which causes a sudden drop in blood pressure. In some cases, anxiety may distract a person from their basic need for food or water, causing hunger- or dehydration-related fainting.
Postural orthostatic tachycardia syndrome
Postural orthostatic tachycardia syndrome (POTS) causes too little blood to flow back to the heart when a person changes position, often when going from sitting or lying down to standing. Similar to vasovagal syncope, it can cause blood pressure to drop very low suddenly.
Following an orgasm, POTS can happen when a person stands, or if they changed position frequently or quickly during sex. Most people with POTS do not have an underlying medical condition, but some may have heart arrhythmias or circulation disorders.
Heart health problems
Rarely, fainting may warn of a problem with the heart or the circulatory system. Some health issues may cause a person to pass out after orgasm.
Some people deliberately pass out during an orgasm or attempt to induce feelings of dizziness that lead to fainting. People may refer to this as autoerotic asphyxiation.
People do it by trying to cut off their supply of oxygen or decrease blood flow to their brain. It is extremely dangerous and can even be lethal.