George Floyd pleaded at least 16 times: “I can’t breathe.” But police officers didn’t really believe him. “He’s talking. He’s fine,” one officer told bystanders. But he wasn’t fine — he was suffocating and was ultimately killed by the police officers.

“The belief that a person’s ability to speak precludes the possibility of suffocation is not true and can have fatal consequences,” write the authors of a paper detailing this myth. The paper is spearheaded by Anica C. Law, who specializes in pulmonary diseases at the Boston University Medical Campus.

It’s not clear exactly where the myth of “speaking means breathing” originated from, but it’s surprisingly pernicious. The day after Floyd’s demise, Mayor Hal Marx of Petal, Mississippi, took to Twitter to post “If you can say you can’t breathe, you’re breathing.”

It wasn’t the first time something like this happened. In 2014, in the wake of Eric Garner’s death under similar conditions (Garner was killed after a police officer, put him in a prohibited chokehold while arresting him), New York Representative Peter King and police officials made similar statements.

Researchers speculate that the myth may originate from an extrapolation of first aid traning on choking. In this training, it is taught that the inability to talk is a clear sign of choking, which is true. But the reverse is not necessarily true, researchers write.

“You can move enough air to produce sound but not be able to breathe enough to sustain the gas exchange needed to prevent organ damage from hypoxemia [insufficient oxygenation]. It is therefore not surprising that such a person as George Floyd may have been able to both generate the sentence “I can’t breathe” and still experience severe air hunger (that is, dyspnea) and decompensate into a state of respiratory failure.”

A 70 kg adult at rest requires 4-5 liters of oxygen per minute, the researchers write. Light muscular activity doubles that oxygen requirement, and someone doing extreme physical activity can require up to 100 liters of oxygen per minute. If this necessary oxygen is not obtained, the consequences can be devastating.

The volume of an ordinary breath is approximately 0.4 to 0.6 liters of total air. With each breath, air is inhaled and reaches the upper airway, trachea, and bronchi. Normal speech only requires 0.05 liters of gas per syllable — thus, saying “I can’t breathe” would only require 0.15 liters of gas. This speech also doesn’t necessarily use the air for breathing.

“George Floyd could have uttered those syllables repeatedly with small breaths that filled only the trachea and bronchi but brought no air to the alveoli, where actual gas exchange happens,” the researchers write.

Not only can someone be able to speak and still be suffocating, the researchers explain, but suffocation is also one of the most uncomfortable and traumatic experiences someone can have.

“Air hunger is the most uncomfortable and emotionally distressing quality of dyspnea. It directly activates the insular cortex, a primal sensory area of the brain that responds to such basic survival threats as pain, hunger, and thirst. Data from studies of war and torture victims show that the sensation of suffocation is the single strongest predictor of posttraumatic stress disorder and can cause more persistent psychological damage than mock execution with a pistol, This finding suggests that clinicians have a fundamental responsibility to serve as advocates for persons who report respiratory distress.”

So it’s not just that Floyd was suffocating, but it was a torturous experience. As a result, statements saying that someone can breathe when they are speaking are not just false, but also cynical and cruel. The researchers published the paper in an attempt to combat such misleading statements and set the record straight based on science and medicine.

“The use of incorrect physiologic statements to justify the force leading to the deaths of Eric Garner and George Floyd is unacceptable. According to our oath as clinicians, it is our responsibility to the public to aggressively correct such misconceptions to prevent further deaths. However, as human beings, we emphasize that it does not take medical training to inherently understand the profound danger and inhumanity behind forcibly inducing respiratory distress in another person.”

The paper concludes that such misleading statements are, at best, thoughtless — and at worst, cruel, toxic, or malicious. People who describe respiratory distress should receive immediate and serious attention.