It has been proven that people who sleep less than six hours or more than nine each night are disposed to a higher risk of obesity, physical inactivity, smoking and alcohol drinking, according to a study made by the U.S. Centers for Disease Control and Prevention.

"Among adults 18 and older who sleep between seven to eight hours a night, only 18 percent were current cigarette smokers compared to over 30 percent of adults who slept less than six hours a night and that is a very large difference," said Charlotte Schoenborn, a health statistician with the National Health Interview Survey of the Centers for Disease Control and Prevention.

26% of those persons who sleep more than nine hours every night are smokers too.

Generally speaking, it is important that any individual sleeps between seven and nine hours per night, with variations determined by age and daily activity.

“Sleep is important to your health, more than just the way you feel on a daily basis. We're learning that these things are connected, and good sleep is something important that people should do, just like exercise,” said Schoenborn, as cited by Bloomberg.

As regards obesity, 33% of the individuals who slept under six hours were overweight, alike 26% of those who oversleep. Normal sleepers had the lowest rate, 22%.

When talking about the alcohol drinking issue, those who sleep the least were the biggest drinkers, as noted in the Washington Post.

The study consisted of door-to-door surveys of 87,000 U.S. adults from 2004 through 2006. This is the reason why it is still not clear whether sleep deficit is the result or the cause for developing unhealthy habits.

Light sleep was explained through the well-known intense stress factors and the numerous worries one has nowadays.