The research team found a U-shaped relationship between heart risk and sleep duration, with risk at its lowest among people who got between six and seven hours of sleep on average.
A lack of sleep already has been linked to poor heart health, said Dr. Martha Gulati, editor-in-chief of CardioSmart.org, the American College of Cardiology’s educational site for patients.
“We have a lot of data related to less sleep,” said Gulati, a cardiologist. She noted that a number of key heart risk factors — blood pressure, glucose tolerance, diabetes and inflammation — are exacerbated by too little sleep.
There’s not as much evidence regarding those who slumber too long and their heart risk, however, Gulati and Gupta said.
Gupta and his colleagues found one possible explanation in their research. Based on patients’ levels of CRP, inflammation accounted for about 14% of heart-related deaths among short sleepers and 13% among long sleepers, versus just 11% of folks who got the optimal six to seven hours of sleep.
“Patients who sleep for six to seven hours have the least CRP, so this inflammation might be driving increased cardiovascular risk,” Gupta said.
It might be that people who sleep longer than seven hours are just getting lousy sleep, and so have to doze longer, Gulati said. Poor quality sleep could be driving the increased risk among late snoozers.
“You wonder if somebody is sleeping longer because they just didn’t get a good night’s sleep,” Gulati said. “I always say there’s good sleep and there’s bad sleep. You might be in bed for eight hours, but is it good quality sleep?”
