A woman saw her life flash before her eyes in a near-fatal drowning incident. Doctors explain why this might happen.

• Some people see their life "flash before their eyes" when they fear they're dying.
• Michele Eason Simone experienced this during a near drowning.

Michele Eason Simone was swimming on the Outer Banks in North Carolina when she felt a rip tide pull her out to sea. As waves crashed over her head and she struggled to breathe, she was horrified to see the lifeguard chatting with someone on the beach, rather than rushing to her rescue. Eason Simone thought she was going to drown.

That's when she experienced something she couldn't explain.

"I started to feel myself start to feel like I was going to black out, but before I did, my short life flashed before my eyes," said Eason Simone, who was 21 at the time. "It was like having a memory of everything that had happened to me in my life show itself to me all at once in the quickest movie you could ever imagine. It was like a universal understanding of every memory in only an instant."

More than three decades later, the experience is still hard to explain, but profound, Eason Simone says. She's not alone. Many people have experienced their lives "flashing before their eyes" when they fear they're going to die. Last month, a man explained on Twitter his experience during a brain surgery gone awry.

"Life flashes before your eyes," he said. "Every memory — I'm telling you, every single memory you've ever made in your life — will rush past you at light speed."

Science has no explanation, but a few theories

Science can't explain why some people experience these memories, which are scientifically known as a life review, says Neuroscientist Hayley Nelson, founder of The Academy of Cognitive and Behavioral Neuroscience. However, there are some theories about what's going on.

"One theory suggests that oxygen deprivation during a life-threatening event can trigger the release of neurotransmitters like glutamate, causing neurons to fire rapidly," Nelson said. "This heightened activity in the visual cortex might lead to the perception of vivid memories and images, potentially contributing to the phenomenon of life review."

Another possible explanation has to do with how memories are stored in the brain. Scientists believe emotionally charged memories are stored in multiple areas of the brain, including the amygdala, the same area that's associated with the fight or flight response.

"When faced with a life-threatening situation, the amygdala is automatically activated, and its involvement could prioritize memories linked to emotions such as fear, love, or regret," Nelson said. "These memories, once retrieved, might be integrated with the ongoing experience, creating a subjective sense of reliving one's life."

Yet Dr. Jeffrey Long, founder of Near-Death Experience Research Foundation, says he's studied experiences like these for decades and never found a physical explanation that makes sense for him.

"I have spent decades trying to find if there's anything in the brain that can account for this," he said. "As a scientist, it would make my life easier." But an explanation, so far, has evaded him. Instead, Long has become convinced that these experiences are signs that life after death exists.

There could be some confirmation bias at play

Many people have heard stories of others having "their life flash before their eyes." That can impact how a person who experiences a life review interprets it.

"The portrayal of life flashing before one's eyes in media and literature can establish expectations," Nelson said. "When people encounter a near-death situation, their brain may engage in a rapid mental review, which they subsequently interpret as aligning with the cultural trope."

Eason Simone had heard about life reviews but was stunned to experience one herself.

"I was shocked by seeing my life flash before my eyes because I had always heard people say that, but to experience it yourself is shocking, and you actually know what it is as soon as it happens," she said. "There's no doubt."

While science can't explain what happened to her, she says that she's come up with her own explanation.

"I do think it was a spiritual and supernatural experience, and I'll never forget it, " she said.