New research suggests the same genes that predict what time you might feel groggy or hungry in the day could also predict what time of day you will die.

A team of researchers stumbled upon the connection while investigating genes that predict what time a person is likely to go to sleep.

“We carried out an initial study to try and find genes that explain why some people are morning people and some people are evening people,” said lead author Dr. Andrew Lim of The University of Toronto, in an interview with CTV’s Canada AM. “What we found was a gene variant such that people with two copies of the early version of the gene have a daily activity rhythm that shifted one hour earlier than people who have two copies of the late version of this gene.”

The research was conducted by measuring the daily rhythms of about 600 elderly people using a specially designed wrist watch and by examining their DNA. But by the team the researchers began analyzing the data, a number of the study’s participants had died.

“We knew what time they had died,” Lim said. “It turns out there’s some other data that suggest the internal biological clock can regulate other things like blood pressure and heart rate, and therefore might potentially regulate things like the risk for heart attacks and other medical events.”

That means the same genes that predict whether a person is an early riser could also help predict what time of day they are at greatest risk of dying.

“It’s significant in a couple of respects,” Lim said. “It points to the significant impact that the internal biological clock has on a number of medical factors, on death itself, in fact. It points to the circadian control of death.”

Lim said the research could lead to greater intervention to prevent death if it’s known what time a person is most likely to die from medical causes. 

“For instance, if we know that someone’s at the greatest risk of dying in the evening at 6 o’clock, then taking cardiac medications just before that might be able to prevent that from happening,” he said.

In addition to the findings about death, the researchers found that about 16 per cent of the population are genetically predisposed to be late risers, while about 30 per cent of the population are genetically inclined to rise earlier.

On average, people are their peak in the late morning, Lim said.