Holding back tears, Sean Cripe implored parents to talk with their kids about the dangers of energy drinks and consuming too much caffeine.

“It wasn’t a car crash that took his life,” he said of his son. “Instead, it was an energy drink. Parents, please talk to your kids about these energy drinks. And teenagers and students: please stop buying them.”

The autopsy showed no “unfounded” or “undiagnosed heart condition,” said Watts, who was careful not to call Davis’ death a caffeine overdose. He added that Davis had “a previous history of drinking” caffeinated beverages but nothing that his family considered to be an addiction.

“A cup of coffee, a can of soda isn’t going to cause this thing,” said Dr. Amy Durso, deputy chief medical examiner for Richland County. “It’s the amount and also the time frame in which these caffeinated beverages are consumed that can put you at risk.”

Part of the danger in what happened to Davis, Watts said, is that caffeine and energy drinks affect people differently.

“You can have five people line up right here and all of them do the exact same thing that happened with him that day – drink more – and it may not have any kind of effect on them at all,” he said.

Dying from too much caffeine is “very rare,” said Cherokee County Coroner Dennis Fowler, president of the S.C. Coroner’s Association. It’s so rare, he’s never seen it happen in South Carolina, he said.

“That’s the only one I’ve heard of,” Fowler said. “We haven’t dealt with it.”

Federal guidelines prevent the sale of energy drinks on school campuses, according to the S.C. Department of Education. Some schools have even pulled caffeinated sodas from their campuses.

A recently published study in the Journal of the American Heart Association found that those who consume energy drinks end up with higher blood pressure levels for a longer period of time than those who drink just caffeine. The study was conducted on healthy volunteers between 18 and 40, after seeing the popularity of energy drinks rise with emergency room visits and deaths.

A 2015 Mayo Clinic study also found that one energy drink can increase the blood pressure of healthy young adults as well as stress hormone levels that also can raise the risk of cardiovascular events. The study, whose participants had an average age of 29, suggested that asking about energy drink consumption should become part of a physician’s routine.