One in three teens is a couch potato, says study

American children are not the only couch potatoes with nearly one third of children globally spending three hours a day or more watching TV or on computers, according to a study of more than 70,000 teens in 34 nations.

From Argentina to Zambia, Regina Guthold of the World Health Organization in Geneva and her colleagues found most children aren't getting enough exercise and it made no difference if they lived in a rich or a poor country.

"With regards to physical activity levels, we did not find much of a difference between poor and rich countries," Guthold says. "Growing up in a poor country does not necessarily mean that kids get more physical activity."