In fact, many AIDS patients say they're fatigued, and report this as one of the most common side effects of HIV treatment. One of the most common causes is anemia.
Anemia is a shortage of red blood cells in the circulating blood.
Besides fatigue, the symptoms of anemia include dizziness and shortness of breath. The hemoglobin in red blood cells carries and releases oxygen throughout the body. Oxygen acts like fuel for the body, providing energy for muscles and organs to work. Energy levels go down due to lack of oxygen-rich red blood cells. The virus itself may decrease production of red blood cells.