Sleeping more than nine hours a day and sitting too much are associated with increased mortality, according to a new study conducted by researchers from the University of Sydney in Australia. The study demonstrated that people who sleep too much, sit more than seven hours a days and are not physically active enough are fourfold more likely to die early than others with healthier lifestyle habits. "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 author Dr. Melody Ding in a press release. Researchers analyzed lifestyle behaviors that are already known to increase the risk of death and disease - smoking, high alcohol intake, poor diet and being physically inactive - and added excess sitting time and too little/too much sleep to the equation. "Our study shows that we should really be taking these behaviors together as seriously as we do other risk factors such as levels of drinking and unhealthy eating patterns," Ding added. The study has been published in the journal PLOS Medicine.