Do you sleep more than nine hours a night? If so, you could be putting your health at risk.
A new study from Australia found that too much sleep coupled with sitting more than seven hours a day could up the risk of early death by more than four times — particularly when added to a lack of exercise. Too little exercise was defined as less than 150 minutes a week in this study.
"Evidence has increased in recent years to show that too much sitting is bad for you and there is growing understanding about the impact of sleep on our health, but this is the first study to look at how those things might act together," said lead study author Melody Ding, PhD, a research fellow at the University of Sydney, in a press release. "When you add a lack of exercise into the mix, you get a type of ‘triple whammy’ effect."
For this study, Dr. Ding and team looked at the health behaviors of more than 230,000 participants from Australia's largest ongoing study — the 45 and Up Study — which is looking at the health of adults age 45 and older as they age.
These researchers focused on behaviors that are known to increase the risk of early death, such as smoking, high alcohol intake, poor diet and physical inactivity. They then added sitting time and sleep into the equation to see what combinations had the greatest impact on a person’s risk of dying early from any cause.
In addition to the risky combination of prolonged sleep, sitting and physical inactivity, Dr. Ding and team found another triple threat: smoking, high alcohol intake and sleeping less than seven hours a night. This combo was likewise linked to a more than four-times greater risk of early death.
Several other combinations more than doubled the risk of early death, including physical inactivity and too much sleep, physical inactivity and too much sitting, and smoking and high alcohol intake.
"The take-home message from this research ... is that if we want to design public health programs that will reduce the massive burden and cost of lifestyle-related disease we should focus on how these risk factors work together rather than in isolation," said study co-author Adrian Bauman, MD, MPH, in a press release.
This study was published Dec. 8 in the journal PLOS Medicine.
The National Health and Medical Research Council funded this research. No conflicts of interest were disclosed.