New research from a US university study says the human brain can remain functioning for a short period after we die, meaning that you know you are dead.
A research team from the Stony Brook University School of Medicine in New York led by Dr Sam Parnia came to this conclusion by studying cardiac arrest cases in Europe and the US.
According to The Daily Mail, the research reveals that some heart attack survivors can accurately recall what was happening around them while they were "clinically dead" before being revived.
Dr Parnia says after your heart stops beating and your body movements fail you may still experience some form of consciousness.
Meaning you are essentially "trapped" inside your dead body with your brain still working for a short time.
There is also evidence to suggest the deceased may even hear themselves being pronounced dead by doctors.
Speaking to LiveScience, Dr Parnia outlined a typical scene that was described by cardiac arrest survivors in his study.
"They'll describe watching doctors and nurses working, they'll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them.
"It [the time a patient is declared dead] is all based on the moment when the heart stops. Technically speaking, that's how you get the time of death," he said.
Time of death is announced when the heart stops, causing brain functions to cease almost instantly, Dr Parnia says.
However, according to Dr Parnia, brain cells can still be active hours after this has taken place.
"If you manage to restart the heart, which is what CPR attempts to do, you'll gradually start to get the brain functioning again.
"The longer you're doing CPR, those brain cell death pathways are still happening — they're just happening at a slightly slower rate.
"What tends to happen is that people who've had these very profound experiences may come back positively transformed," Dr Parnia says.
According to the Daily Mail, "the aim of his research is to improve the quality of resuscitation and prevent brain injuries while restarting the heart."
