Fatigue and weakness
There is a sensation of weakness and lack of energy because cancer lowers the number of red blood cells in your blood and, consequently, lesser oxygen to provide power. The patients with lung cancer experience persistent weakness and fatigue, and no matter how much the person rests or sleeps, there is no relieving from fatigue. The destruction of red blood cells and the lack of energy available for the body to make enough red blood cells make the person feel tired and weak all the time. The systemic weakness symptom is prevalent and becomes intense with the progression of cancer.