There are many theories about how onset is triggered, but the end result seems to be that the immune system becomes stuck in a state of hyper-activation. This involves the chronic overproduction of chemicals which ordinarily help activate a healthy immune response. Many patients consider the cognitive symptoms the most devastating, more than even the fatigue, pain, or the inability to work. The situation is made worse by the fact that to cope with or adjust to the debilitation of the illness requires mental and emotional resources. With these disturbed, the sense of helplessness and frustration can be compounded.
Problems can be either of interrupted sleep or inability to remain awake.
And when sleep is managed, it is not refreshing sleep. Rather, one awakens still feeling exhausted, or may feel exhausted after just a few minutes out of bed. Good quality rest is necessary in order for the body's self-repair mechanisms to work effectively, and it takes time for the immune system to heal itself. Yet because of the chronic immune activation, the immune system is churning out substances around the clock which disturb the sleep center of the brain. In addition, many people with CFS have chills or night sweats which add to the difficulty.