Chronic fatigue syndrome
If you’re tired all the time, it may feel like you have a chronic condition—but it’s probably not this one. Also known as myalgic encephalomyelitis, chronic fatigue syndrome (CFS) affects between 836,000 and 2.5 million Americans, according to the CDC.
Aside from experiencing exhaustion for at least six months, you would also likely have flu-like symptoms, brain fog, and unexplained muscle or joint pain—and you would feel worse after even mildly exerting yourself.
So, what could your seemingly constant fatigue be attributed to? If it’s not your lifestyle—e.g., too little sleep, too much stress, or obesity—it could be a wide range of medical conditions, including a sleep disorder, a heart or lung problem, anemia, mononucleosis, lupus, or a mental-health issue.