Symptoms Although its name trivializes the illness as little more than mere tiredness, chronic fatigue and immune dysfunction syndrome (CFIDS) brings with it a constellation of debilitating symptoms. CFIDS is characterized by incapacitating fatigue (experienced as profound exhaustion and extremely poor stamina) and problems with concentration and short-term memory. It is also accompanied by flu-like symptoms such as pain in the joints and muscles, unrefreshing sleep, tender lymph nodes, sore throat and headache. Post-exertional malaise is a hallmark of CFIDS and as the name implies, it is a period of profound fatigue that follows mental or physical activity and requires twenty-four hours (or longer) to recover. People with CFIDS (PWCs) have symptoms that vary from person to person and fluctuate in severity. Specific symptoms may come and go, complicating treatment and the PWC's ability to cope with the illness. Most symptoms are invisible, which makes it difficult for others to understand the vast array of debilitating symptoms with which PWCs contend. Other Common Symptoms Additional symptoms are frequently reported by PWC's such as word-finding difficulties, inability to comprehend/retain what is read, inability to calculate numbers and impairment of speech and/or reasoning. PWCs also have visual disturbances (blurring, sensitivity to light, eye pain, need for frequent prescription changes); psychological problems (depression, irritability, anxiety, panic attacks, personality changes, mood swings); chills and night sweats; shortness of breath; dizziness and balance problems; sensitivity to heat and/or cold; alcohol intolerance; irregular heartbeat; irritable bowel (abdominal pain, diarrhea, constipation, intestinal gas); low-grade fever or low body temperature; numbness, tingling and/or burning sensations in the face or extremities; dryness of the mouth and eyes (sicca syndrome); menstrual problems including PMS and endometriosis; chest pains; rashes; ringing in the ears (tinnitus); allergies and sensitivities to noise/sound, odors, chemicals and medications; weight changes without changes in diet; light-headedness; feeling in a fog; fainting; muscle twitching; and seizures.