hold breath by holding RMB in gunsight view
hold own breath for comparison
realize you could have easily held your own breath 2~3x as long as your "trained soldier" (note how soldier is extremely winded, as if nearly fainted)
mentally adjust your comparison as needed, to account for fitness and stamina differences between yourself sitting down and a trained soldier after some running
reckon the obvious health crisis that afflicts all of ArmA's infantry