Mortarmen conducting combat operations must perform complex collective and individual tasks without adequate sleep and under stress. All soldiers experience the fear of death or being wounded, or the fear of failing in the eyes of one's comrades. Smoke, darkness, fog, rain, snow, ice, and glare make it hard to see. The extended wear of night vision goggles, protective masks, or laser protective lenses causes stress. A soldier's performance suffers during normal sleeping hours due to the disruption of the normal schedule.
Mental stress results from making vital decisions with little time and insufficient information.
It is increased during times of great confusion and exposure to danger. Working the muscles faster than they can be supplied with oxygen and fuel can cause soldiers to function poorly without rest. Extreme cold, heat, wet, or thirst add greatly to the level of individual stress. As sustained operations continue, all soldiers begin to show effects of general fatigue and lack of sleep. Unless this is counteracted, mortar performance declines rapidly.