Fatigue is one of the most common symptoms of MS. It is characterized by the sudden loss of energy and the inability to continue an activity that is out of proportion to the activity undertaken. Patients with MS often experience a particular type of fatigue, or lassitude, that occurs daily, worsens as the day goes on, is aggravated by heat, and comes on more easily than normal fatigue. This “invisible” symptom can have a major impact on people’s lives. The following tips may help lessen fatigue’s impact on your daily life.