Fatigue is a symptom, not a disease, and it's experienced differently by different people. This report, entitled Boosting Your Energy, describes different kinds of fatigue and ways to improve your energy level. For example, the fatigue you feel at the end of a long day or after a time zone change might feel similar to the fatigue resulting from an illness. The difference is that fatigue from stress or lack of sleep usually subsides after a good night's rest, while other fatigue is more persistent and may be debilitating even after restful sleep.
How do you know if your low energy is caused by underlying disease or is the result of lifestyle factors, stress, poor diet, lack of sleep, or normal aging? Harvard's Special Health Report, Boosting Your Energy, provides advice and information from world-renowned medical experts to help you discover the cause and find the right treatment or lifestyle changes. It includes a Special Section: A 6-Step Plan to Jump-Start Your Natural Energy.