According to Sax Institute's 45 and Up Study published in "PLOS Medicine," a person who sleeps too much is four times likely to die early. More than 9 hours of sleep a night is considered too much. 

Dr. Melody Ding, the lead author of the study, together with his team from the University of Sydney analyzes data taken from more than 230,000 participants. The team looks closely at lifestyle behaviors that are known to increase disease and even death like alcohol consumption, cigarette smoking, suspicious diet and sedentary lifestyle when combined with length and frequency of sleep. They have taken different combinations with all of these factors and zero down on the groupings that had the most impact on person's risk of dying. The data are surprising as they show the most at-risk group is the one with sedentary lifestyle with sleeping for more than 4 hours.

"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," Dr. Ding said. "When you add a lack of exercise into the mix, you get a type of 'triple whammy' effect. Our study shows that we should really be taking these behaviours together as seriously as we do other risk factors such as levels of drinking and unhealthy eating patterns. "

Below are the combinations that led to more than double the risk of early death:

  • Being physically inactive + too much sleep
  • Being physically inactive + too much sitting
  • Smoking + high alcohol intake

"These non-communicable diseases (such as heart disease, diabetes and cancer) now kill more than 38 million people around the world - and cause more deaths than infectious disease. Better understanding what combination of risk behaviours poses the biggest threat will guide us on where to best target scarce resources to address this major - and growing - international problem," Professor Adrian Bauman, co-author of the study, added.