by Aimee Keenan-Greene

Until now, it has just been a theory that babies grow when they sleep.Now, researchers can now link sleep and episodic (saltatory) growth spurts in infants.Scientists from the Department of Anthropology, Emory University, Atlanta and the Departments of Pharmacology and Medicine, University of Virginia Health System, Charlottesville, VA, examined  daily diaries from parents who recorded sleep onset and awakening for 23 infants (14 females) over 4-17 months - in all close to 5798 notations. 


The results, in this months issue of the journal Sleep, says growth spurts in a babies length followed increased sleeping and nap time and  usually occurred within two days of the increased sleep.

The chances of a growth spurt increased by 43 percent for each nap and by increased by 20 percent for each additional hour of sleep.

Children need about 14 hours of total sleep on average through the first year of life.

Teens need about 9 hours of sleep daily.

Dr. Judith A. Owens, MD, and researchers at Hasbro Children's Hospital, studied 201 students in grades 9 through 12 attending classes at 8:30 a.m. instead of 8 a.m. for a two-month period to see if starting school half an hour later lead to a significant improvement in the mood, alertness and motivation of high school students.

Students who completed online surveys before and after the time change reported at least eight hours of sleep per night increased from 16.4 percent at the start of the study to 54.7 percent after two months. Students who reported feeling at least somewhat unhappy or depressed dropped by about 20 percent.

As we age, sleep is key to our brain function. A new study in the journal Nature says the problem-solving brain regions of rats fell into a kind of 'local sleep' even though overall brain activity, and outward behaviors, suggested the animals were fully awake. They did have trouble completing challenging tasks. This condition is also likely to occur in sleep-deprived teens and adults. 

About 29 percent of U.S. adults reported sleeping fewer than seven hours per night, and 50 to 70 million had chronic sleep and wakefulness disorders in 2008, according to the U.S. Centers for Disease Control and Prevention.