LOS ANGELES, Feb 14: Sleeping longer — like getting eight hours or more a night — could shorten your life, according to a study of the nighttime habits of more than a million Americans released on Thursday.

Researchers from the University of California at San Diego found in a six-year study of adults aged 30 to 102 that people who sleep five to seven hours a night live longer than those sleeping eight hours or more.

The study found little, if any, connection between death rates and insomnia, which it said patients commonly complain of even when their sleep duration is within normal ranges, but said sleeping pills actually increase the risk of death.

“People who sleep five, six or seven hours have nothing to worry about. There is no evidence that people need eight hours of sleep ... the only basis for that is it’s what grandma used to say,” Dr Daniel Kripke, a UCSD professor of psychiatry and the study’s lead author, said in an interview.

He said people who take sleeping pills were shown to have a slightly higher death rate than others, but because the data was collected in the 1980s, the results are not necessarily reflective of newer types of sleeping pills.

Kripke, an eight-hour-a-night sleeper, said the average American gets six-and-a-half hours of shut-eye, which is just fine. “Neither in terms of health or survival is there any evidence that eight hours of sleep is better than six or seven. Nor is there any evidence that longer sleepers are rich or have more fun,” Kripke said.

The study was not designed to say how much longer a person who gets between five and seven hours of sleep will live when compared to people who average eight or more hours.—Reuters