ME/CFS is a complex, debilitating disease affecting 3 million Americans and 20 million worldwide. It can be triggered by infection, immunization, anesthetics, chemicals, toxins or blood transfusions. Its core symptoms include profound fatigue, pain, cognitive impairment, orthostatic intolerance, and sleep issues. These worsen with activity or stimulation, termed post-exertional malaise, are not improved by sleep, and persist indefinitely. Patients are prone to developing dysautonomia, insulin resistance, immune dysfunction, hypothyroidism and gynecological issues. They succumb to cancer and heart failure earlier than the general population and experience a quality of life lower than in most chronic diseases.
Long COVID has the same symptoms as ME/CFS, including post-exertional malaise – Davis 2021
 Lam MH-B. Mental Morbidities and Chronic Fatigue in Severe Acute Respiratory Syndrome Survivors: Long-term Follow-up. Arch Intern Med. 2009 Dec 14;169(22):2142.
Chronic Lyme disease, associated with tick-borne bacteria, is characterized by fatigue, sleep impairment, cognitive dysfunction, pain, depression and post-exertional malaise. It affects 1.9 million Americans
Fibromyalgia is characterized by chronic widespread pain at multiple tender points, fatigue, muscle weakness, joint stiffness, mood disorders, cognitive dysfunction and insomnia. It can be triggered by infection, physical trauma, whiplash, vaccinations, chemicals, post-surgery and emotional stress. It affects 4-10 million Americans.
Post-traumatic stress disorder is triggered by exposure to a traumatic event with the potential for, or actual occurrence of, grave physical harm. It is characterized by intrusive memories (flashbacks, nightmares), changes in emotional reactions (avoidance, negative thoughts and moods), hyper-arousal, hyper-vigilance, sleep disturbances and cognitive difficulties. It affects 10 million Americans.
Multiple chemical sensitivities is thought to be triggered by chemical exposure. Its symptoms can include headache, fatigue, dizziness, nausea, congestion, itching, sneezing, sore throat, chest pain, changes in heart rhythm, breathing problems, muscle pain or stiffness, skin rash, diarrhea, bloating, gas, confusion, trouble concentrating, memory problems, and mood changes. It affects 25 million Americans.