7 Healthcast: Sleep studies

"Looking at the effect of smoking on brain wave function, it turns out that when they looked at this group of smokers they actually had a lighter sleep pattern," said sleep expert Kenneth Sassower.

Researchers say smokers may not sleep as well because they're having nicotine withdrawals during sleep causing them to wake up.

But Dr. Sassower says there could be other reasons too. For example, smoking puts you at risk for sleep apnea.

And another study finds the number of hours your child sleeps could affect their weight.

Researchers at Johns Hopkins University analyzed 17 previous studies on kids sleep and obesity. The findings: kids that don't get enough sleep are more at risk of being overweight.

Dr. Sassower says a chemical change in the brain could be the reason.

"It is actually a small protein in the brain that is related not only to appetite but also to sleep deprivation and sleep loss," Sassower said.

Dr. Sassower recommends children under five get at least 11 hours of sleep. Kids 5 to 10 should have at least 10 hours, while children over ten need nine hours.

"Even teenagers need at least 8 to 9 hours of sleep," Dr. Sassower said.

Dr. Sassower says some of the reasons kids are not getting enough sleep is that both parents and children are over scheduled with school, work and outside activities.

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