How Sword Swallowing Works

The human gastrointestinal (GI) tract is made of two types of tissue — skeletal muscle and smooth muscle — and a lubricating layer known as the mucosa. In general, the movement of skeletal muscle is voluntary. When you talk, type, blink and move, you're using skeletal muscle. The movement of smooth muscle, on the other hand, is generally involuntary. Smooth muscle is responsible for actions like the dilation of blood vessels and movement of food during digestion. Many of your body's activities, including breathing and eating, require the participation of both skeletal and smooth muscle tissue.

The portions of the GI tract made of skeletal muscle include your mouth, your pharynx and the upper portion of your esophagus, which connects your throat to your stomach. These are the parts of your GI tract that you have conscious control over. When you swallow, you consciously use your tongue to move the food toward your pharynx. Your larynx then moves upward, and a ring of muscle called the upper esophageal sphincter relaxes. This allows the food, or bolus, to move into your esophagus. A flap of tissue known as the epiglottis seals off your windpipe during this process so the food doesn't go into your lungs.

The actions of the rest of your GI tract are involuntary. When the bolus reaches the part of your esophagus lined with smooth muscle, an automatic process called peristalsis takes over. The ring of muscle tissue just above the bolus squeezes together, forcing the bolus down toward the stomach. Then, the process repeats itself until the food reaches the stomach. A second sphincter, the lower esophageal sphincter, relaxes to allow the bolus into the stomach.

This whole process takes place in very close proximity to other organs in your body, including your:

A number of other important structures, like blood vessels and lymph nodes also surround your throat, esophagus and stomach. These are the structures that the sword passes by on its way down.

We'll look at the process of swallowing a sword step by step in the next section.

When a performer swallows a sword, it takes the same path that food does, but the process is significantly different. Swallowing food involves the contraction of several muscles. Sword swallowing, on the other hand, requires deliberate relaxation of the upper GI tract. Here's what happens:

Sometimes, the sword also passes the lower esophageal sphincter and enters the stomach, but this doesn't necessarily happen every time. The distance from the teeth to the portion of the stomach that connects to the esophagus, known as the cardia, is approximately 15 inches (40 centimeters). The Sword Swallowers Association International (SSAI) defines a sword swallower as a person who can swallow a 15-inch (40-centimeter) sword, which wouldn't necessarily enter the stomach. The SSAI's maximum recommended length for a swallowed sword is 33 inches (83 centimeters), which would put the tip of the sword well into the performer's stomach [source: swordswallow.com].

Those three steps can sound deceptively easy, but sword swallowing is extremely difficult to master. It's also not something that people should try without the help of an experienced professional. We'll look at why — and what can go wrong — in the next section.

The process of swallowing a sword involves more than just lining everything up and letting gravity do its work. In order to successfully swallow a sword, a performer must learn to relax muscles that are typically not under voluntary control. These include the upper and lower esophageal sphincters and the muscles of the esophagus that are involved in peristalsis.

He must also make the performance look easy, which can be a challenge. If you have ever swallowed a mouthful of food that was too large or not thoroughly chewed, you know how sensitive your esophagus can be. A sword swallower must move a cold, rigid sword down the entire length of his throat and esophagus without showing any discomfort.

The human body also has a defense mechanism that has the sole function of preventing everything but chewed, swallowed food from entering the throat — the gag reflex. When you accidentally touch the back of your throat with your toothbrush and involuntarily gag, you've activated this reflex. In some people, the gag reflex is quite sensitive and can be activated by touching the back of the mouth. In others, the gag reflex is minimal.

A successful sword swallower has to learn to ignore his gag reflex. This is not easy. Reflexes are involuntary — they happen without deliberate effort or thought. Your reflexes allow you to jerk your hand away from a hot stove, and they're also involved in the involuntary portions of body processes like urinating. All of these reflexes are vital to survival, and all of them happen without the involvement of your conscious mind.

Reflexes involve several physiological components that combine to form a reflex arc. Here's what happens:

In the case of your gag reflex, nerve endings in the back of your throat detect an intrusive object. This generates nerve impulses, which a neuron carries to the integration center in your brain stem. The brain stem, using a motor neuron, instructs the muscles in your throat — the effectors — to contract. The result is a retch intended to force foreign objects out of the throat and mouth. All of this is involuntary and happens in an instant.

Learning to ignore an involuntary process takes a tremendous amount of practice. In the case of sword swallowing, it generally involves deliberately activating the gag reflex over and over. The process can cause vomiting and considerable discomfort. It also dulls or removes a process intended to protect the person from harm. This is one of the many reasons why sword swallowing is dangerous. We'll look at some of the hazards of sword swallowing in the next section.

Sword swallowing involves deliberately conditioning your body to do something its defense mechanisms prohibit, so it's not surprising that it's a dangerous activity. It's also not widely studied in the field of medicine, perhaps because there are so few sword swallowers. The results of the most thorough medical study appeared in the British Medical Journal. The study involved the voluntary survey of 110 English-speaking sword swallowers. Forty-six of the 48 performers who responded consented to having their data used in the study. Thirty-three of the respondents included information about their medical histories. From most to least common, the side-effects they experienced from sword swallowing included:

Some respondents described seriously injuring themselves shortly after an unusually painful sword-swallowing performance. A logical conclusion is that the swelling and tissue trauma associated with minor injuries may lead to more severe injuries. Sinus infections are another potential side effect, since the practice involves guiding a non-sterile surface past tissues that connect to the sinus passageways.

Since the survey polled living sword swallowers, it did not include discussions of deaths caused by sword swallowing. However, other medical literature has cited sword swallowing as a cause of death. Another British Medical Journal article describes a sword swallower who died after trying to swallow an umbrella [source: BMJ]. Sword swallowing also appears in historical books on medicine, some of which present fantastic claims of people completely swallowing knives and living with the foreign objects in their stomachs for years at a time.

Not all medical discussions of sword swallowing involve injuries and deaths, though. In the mid-1800s, during the early development of endoscopy, or the examination of the interior of the human body using a scope, the available tools were generally rigid. Researchers sometimes worked with sword swallowers, whose throats could accommodate the inflexible instruments.

As with other dangerous performance arts, such as fire breathing, the human blockhead trick, and walking across glass, there's no real way to make authentic sword swallowing significantly safer. However, since the practice has most likely existed for thousands of years, it's also not likely to fade away any time soon. To learn more about sword swallowing and related acts, check out the links on the next page.