Too much of something is said to be hazardous and this saying can also be applied to resting habits. In a new study, researchers found that sleeping for more than nine hours and sitting for prolonged periods of time can actually shorten life.

The majority of diseases worldwide is attributed to numerous lifestyle risk behaviors, such as smoking, lack of physical activity and poor diet. Such factors tend to pile up in populations, instigating interdependent effects on health

Poor health habits have already been recognized to cause hazards, but putting these factors together will give clinically vital data that can help determine the combined effects of these risk factors.

Researchers from Sax Institute reviewed behavioral lifestyle risk factors of 231,048 Australians aged 45 years or older during six years of follow-up. The participants all answered a lifestyle survey as baseline data. The researchers then scored six lifestyle behaviors for each study subject and combined the scores to come up with a lifestyle risk index.

The results of the investigations show that an individual with unhealthy sleeping habits (defined as sleeping for less than seven or more than nine hours a day) and prolonged sitting (sitting for more than seven hours a day) is four times more likely to have a shortened life compared to those who do not employ such habits.

"When you add a lack of exercise into the mix, you get a type of 'triple whammy' effect," lead author Dr. Melody Ding said. Too little exercise is defined by the authors as having less than 150 minutes of physical activity per week.

The researchers also looked into other combinations to determine which groupings had the most significant impact on a person's risk of early mortality due to any cause. Some of the other combinations that double the risk of death include:

• Too little exercise plus too much sleep
• Too little exercise plus too much sitting
• Smoking plus increased alcohol consumption

In the end, the authors said their study was able to reaffirm the value of a healthy lifestyle. The identified combinations of unhealthy lifestyle behaviors now warrant development of new measures to prevent chronic diseases.

The study was published in the journal PLOS One on Tuesday.

Photo: Sarah Nichols | Flickr