Why Do People Pass Out?

Recently I saw a video of a young man and his girlfriend strapped into an amusement park ride that took them to the top of a tall pole, paused, then suddenly dropped them, and repeatedly stopped and dropped. They both must have been on the ride for the first time because they each expressed concern and even suggested that maybe they should get off.

But before they could execute that suggestion, they were rapidly pulled to the top of the pole and let go. The video shows that the girlfriend screamed and to some degree, seemed to enjoy the ride. The young man, however, screamed and promptly fainted. What made it interesting was that throughout the entire ride, the girlfriend didn’t notice. This young man would wake up screaming and then faint again, over and over. So, why did he keep passing out while the girlfriend did not?

These brief periods of fainting—greyouts or blackouts—are known as syncope. Gravitational forces (G-forces) and abrupt changes in acceleration and deceleration are the reason that people pass out on rides. A roller coaster accelerates upward, forcing blood downward toward the lower extremities, away from the brain, temporarily reducing the oxygen supply to the brain. The individual will experience loss of peripheral vision, what they see is dimmed (a greyout) or they experience total temporary blindness (a blackout).

The body, in an effort to counteract all this, increases the heart rate, and blood vessels constrict in an effort to maintain adequate blood flow to the brain. But because of the G-forces, these compensation efforts may not be sufficient causing a lack of oxygen to the brain and resulting in syncope.

The balance systems—vestibular and autonomic nervous systems—can also play a role. The autonomic nervous system controls involuntary bodily functions. This system can be overwhelmed by extreme sensory input from, let’s say, a roller coaster. This triggers a sudden drop in heart rate and blood pressure (a vasovagal response), which in turn reduces blood flow to the brain and a person will faint. The vestibular system provides information about motion, balance, and spatial orientation. It is located in the inner ear. On a fast-moving ride, what the eyes see conflicts with what the inner ear feels. This mismatch leads to motion sickness symptoms and contributes to the vasovagal response, resulting in overstimulation of the vagus nerve and a temporary loss of consciousness.

But why did the young man do all the fainting, but the girlfriend did not at all? Several other factors can increase a person’s susceptibility to passing out. Dehydration and hunger can reduce blood volume, and the body is then less able to cope with the changes that occur when experiencing G-forces. Fatigue lowers the body’s resilience to stress. Pre-existing medical conditions like low blood pressure and heart issues can contribute to the fainting episodes. Even psychological factors such as anxiety and fear can trigger an adrenaline rush, increasing the heart rate and blood pressure, and once the intense portion of the ride is over, there is a sudden drop resulting in fainting. Hyperventilation or heat illness can also cause a person to faint.

Fainting, without the sudden ups and downs of an amusement park ride, is still caused by a lack of blood flow to the brain. This lack of blood flow can be caused by many of the same things. But just fainting can also be a sign of a serious or even life-threatening condition. If you experience any of the following symptoms, you should take immediate steps to prevent fainting, but you should still try to determine why you felt like fainting.

While fainting can happen and there’s nothing you can do to stop it, there are things you can try when you feel a faint coming on:

• Make a fist
• Cross your legs
• Squeeze your thighs together
• Tighten the muscles in your arms
• Lie down or put your head between your knees

A person may faint only occasionally as a result of easily-recognized reasons, but if a person experiences frequent fainting spells, it might be time to consult a healthcare provider to determine the cause.

Did You Know?

Fainting happens most often to people between the ages of 10 and 30 years, and in those 65 and older.

Commonly found in males, micturition syncope can cause a person to pass out when they urinate, cough or stretch.

Standing for long periods with knees locked can cause you to faint. This is a result of blood pooling in your leg veins.

Source: biologyinsights.com/why-do-some-people-pass-out-on-rides; verywellhealth.com/causes-of-fainting