Whether these faints are provoked by what’s on stage or what’s happening in viewers’ minds, it’s an emotional distress that is prompting audience members to pass out. Physically, they’re probably perfectly safe. So what’s causing them to faint?
Broadly speaking, there are three main types of faints: ones stemming from serious heart problems (cardiac syncope), ones where blood pressure dips due to standing up (orthostatic syncope), and ones caused by specific triggers (reflex syncope). While plenty of animals faint—miniature schnauzers are prone to irregular heartbeats, for instance, and squirrel monkeys can have low blood sugar—reflex faints appear to be unique to humans.
Reflex faints are activated by the nervous system, which slows down the heart rate and/or lowers the blood pressure in response to strain, leading to reduced blood flow to the brain. Triggers for this can be surprisingly benign. For some people, laughing, coughing, swallowing, urinating, or blowing a trumpet can lead to syncope. Win-Kuang Shen, a Mayo Clinic cardiologist and coauthor of the recently published clinical guidelines for assessing and treating syncope, explained that the nervous system doesn’t distinguish between physical and emotional distress; they’re both stress inputs, leading to the same response.
The most common reflex faints are known as vasovagal faints. Generally, when people describe ordinary fainting, they’re referring to vasovagal syncope. “One-third of the population has vasovagal faints,” said J. Gert van Dijk, a neurologist at Leiden University in the Netherlands.
The name derives from “vaso” (blood vessels) and the vagus nerve, which extends from the brain to the abdomen, spreading fibers to major organs like the heart and lungs. The vagus nerve is responsible for regulating heart rate, sweating, and other essential functions. Triggers like the ones mentioned above lead to confusion in the mechanism for controlling heart rate and blood pressure. Vasovagal faints are essentially a protective mechanism.
Let’s take an example. You’re watching a scary movie or a play about ghosts. During the tense bits, adrenaline is released into your bloodstream. This leads your heart to beat faster and the blood flow to your muscles to increase. Essentially, the nervous system is bolstering your energy and preparing you to fight, as it doesn’t make the fine distinction that what’s on screen or on stage can’t actually hurt you. The parasympathetic nervous system, of which the vagus nerve forms part, seeks to calm you down by lowering your blood pressure and heart rate. Sometimes, though, it overshoots, and your blood pressure might drop too much or your heart rate might slow too far.
Emotional faints are the most common kind of faints overall. These can be activated by fear, excitement, or anxiety, such as one might experience at an intense play like 1984. As van Dijk commented, “It looks horrible and it grabs you emotionally. And if you have the type of vasovagal faint which is prone to emotional triggers such as seeing blood or pain, that can certainly evoke fainting in susceptible people.”