They even found a measurable increase in the condition for every two hours sitting in a car.

VOA: special.2009.07.14

So the Institute of Medicine proposed that residents be required to get five continuous hours of rest for every sixteen hours on duty.

VOA: special.2010.07.13

A new study found better results in four-year-olds who go to bed around the same time every night and sleep at least eleven hours.

VOA: special.2010.06.09

They believed him. And they began to dance for long hours every day.

VOA: special.2010.04.08

She says people spend millions of hours on that website every month.

VOA: special.2010.06.28

She says being a mom is hard. "Because you have to get up every two hours in the middle of the night, and you can't go out and say 'I am going to buy this for myself.'

VOA: special.2010.05.13

plays the title character in "Jonah Hex." Brolin says it took three hours in the make-up chair every day to give the character his disfigured look.

VOA: standard.2010.06.20