Operations in MOPP4 cause faster degradation of combat effectiveness. Though essential for endurance, sheer determination cannot offset the cumulative effects of sustained sleep loss. A unit that is subjected to extensive sustained operations requires a long period of rest and recuperation to regain combat effectiveness. Continuous operations cause a slower, but no less serious, degradation of combat effectiveness. Whether a task is degraded by loss of sleep depends on many interacting and sometimes counteracting factors.
Complicated tasks are more stimulating to the brain and require more training to master.
A simple task requires less training to do but can be boring. A soldier needs a high level of arousal to perform a task well after sleep loss. The FDC computer operators perform the most complex tasks and are usually the first to show the effects of sleep loss. This applies to both physical and mental tasks. Simple lifting, digging, or marching can be stable.