What causes increased fatigue?

Fatigue is a relative term, meaning each of us evaluate our current energy level based upon how we feel most of the time. For example, people who are very energetic and go nonstop from early morning to late at night might say they have fatigue if they felt like most of us do every day.

Despite that variation, most people do have a sense when their level of fatigue feels like something more than just being tired. If that's case, even if it lasted only seven to 10 days, it's time to call your doctor's office. Signs that your fatigue might be related to an underlying illness or infection include low grade fever, night sweats, shortness of breath or loss of appetite. Other triggers for calling your doctor might be waking up exhausted despite a good night's sleep, not feeling motivated to begin the day, or struggling to do activities that are usually easy for you.