It's the most common complaint doctors hear and one of the hardest to diagnose. It can reflect a serious ailment, like cancer or heart disease. It means different things to different people. Uncovering the cause of low energy may take a lot of time and many tests, and even then, a satisfactory diagnosis may be elusive.
People experience low energy in different ways.
It can be a physical tiredness from overworking the body or mental drowsiness during a day at the office, and it may be hard to distinguish from boredom. Doctors obtain the patient's history and do a physical examination, then decide if additional tests are in order. Most low-energy problems aren't linked to cancer or other serious diseases, says Dr. Tom Delbanco, chief of general medicine and primary care at Beth Israel Deaconess Medical Center in Boston. Also, if you're not a naturally energetic person, says Delbanco, you shouldn't necessarily expect your energy level to match that of someone who is. When the tiredness is a new complaint, it's important to make sure the reason is a benign one, not disease.