How long is it safe for someone to stay upside down?

How long can the human body safely remain in an inverted position? Hans Neleman/Getty Images

Important Points to Note

Do you ever feel a sense of panic when hanging upside down? Like your head might explode? Or that your saliva could pool in your nose and suffocate you? Perhaps you worry that your eyes could pop out and fall to the ground?

Rest assured, none of those extreme things will happen. However, staying inverted for too long isn't entirely safe either. While it may not cause your eyeballs to eject (although temporary vision loss can sometimes occur in some individuals), it could ultimately prove fatal.

When Inversions Become Deadly: The Nutty Putty Cave

In 2009, John Jones, a man from Utah, tragically passed away after being stuck upside down for 28 hours at a 70-degree angle in the

Nutty Putty Cave. Although rescue teams rushed to save him, the narrow walls of the cave made it impossible to reach him in time, and he likely succumbed to asphyxiation.

Effect on the Lungs

It turns out that your lungs are designed to rest above the other organs for a reason. Being delicate, they can quickly get compressed by the heavier, larger organs such as the liver and intestines, which usually sit below them.

This isn't much of an issue when you're lying on a slanted surface with your feet slightly raised above your head, but when your head is positioned directly beneath your feet, your lungs simply can't take in enough oxygen due to the limited space available.

Natalie Morales (L) and Savannah Guthrie appeared on NBC's "Today Show" testing an inversion table, which suspends a person upside down for a short period. Peter Kramer/NBC/NBC NewsWire/NBCU Photo Bank/Getty Images

But it's not only the lungs that are at risk during prolonged periods of inversion. Our bodies are designed to circulate blood efficiently when standing upright, and our blood vessels are specifically adapted to prevent blood from pooling in our feet.

However, this system is a one-way street — our bodies weren’t designed to prevent blood from pooling in the brain. When this happens, it can cause various complications, including ruptured blood vessels, which may lead to a brain hemorrhage.

Effect on the Heart

Medical experts believe that heart failure is the leading cause of death in most fatalities from being upside down, for similar reasons to why the brain suffers: When your head is below your feet, your heart slows its pumping and begins to receive more blood than it can handle at once. It struggles to maintain blood pressure and eventually fails to circulate enough blood to sustain the body’s vital functions.

The Mesentery

The mesentery, a tissue fold that attaches the intestines and other abdominal organs, primarily functions to secure the intestines in place. It prevents the intestines from shifting or becoming twisted.

By stabilizing the abdominal organs, the mesentery ensures that the diaphragm, which plays a crucial role in breathing, has enough room and freedom to move. A properly positioned diaphragm can expand and contract efficiently, allowing for effective inhalation and exhalation.

Advantages of Inversion

Here’s the twist: While hanging upside down can occasionally result in death, if done in short intervals, it offers several significant health benefits.

Inverted positions help blood flow from the feet, legs, and pelvis back toward the heart and lungs, where it replenishes with oxygen. Research has shown that brief inversions over time can lower resting heart rate, boost overall endurance, and improve the body's efficiency in using oxygen during physical activity.

"In yoga, inversions are seen as beneficial in numerous ways; headstands and shoulderstands are some of the most essential asanas, purifying the lymphatic system and stimulating all bodily systems," says Julie Phillips, an aerial yoga and dance instructor at Canopy Studio in Athens, Georgia.

"Yogis are known to hold inversions for long durations — up to 12 minutes, and some even claim to hold them for hours. Personally, I don't sustain inversions nearly that long, but I find them incredibly therapeutic."

Although inverse suspension can be risky, it's actually quite rare for people to die from it.

Worried about getting stuck upside down on a roller coaster? While it's not impossible, in 1997, a group of people found themselves in that exact situation for an hour and a half — and everyone made it through safely.

When Does Inversion Become Dangerous?

There doesn't appear to be a clear rule on how long it’s safe to stay upside down. For example, individuals with heart conditions are at much higher risk in such situations, and younger, healthier people tend to survive longer than the elderly or ill.

The general rule seems to be: If you’re upside down and start feeling like it’s too much, it’s time to stop.

"In my aerial yoga classes, we typically spend five minutes — sometimes longer — with students hanging upside down," says Phillips, "but I make it clear they can move in and out of the inversion as needed, and I stress they should come down if it ever feels overwhelming."

Illusionist David Blaine hung upside down at New York's Trump Tower to announce a September 18, 2008, endurance challenge where he spent a majority of 60 hours suspended upside down. Brad Barket/Getty Images