U.S. Army Soldiers sleep in a hasty fighting position

U.S. Army Soldiers sleep in a hasty fighting position on a cold morning after a night patrol in the mountains near Sar Howza, Paktika province, Afghanistan, Sept. 4, 2009. The Soldiers are deployed with Bulldog Troop, 1st Squadron, 40th Cavalry Regiment. People can lessen the effects of sleep deprivation during long operations by taking precautions such as allowing Soldiers seven to nine hours of sleep regularly for five to seven days before the mission and allowing Soldiers to sleep who are not mission essential at the moment, according to Col. Vincent Mysliwiec, a sleep medicine specialist with 121st Combat Support Hospital, Brian Allgood Army Community Hospital in Yongsan, South Korea. (U.S. Army photo by Sgt. 1st Class Andrew Smith)