Those suffer with fatigue often describe it as a feeling of weariness or tiredness, exhaustion and lack of energy. Fatigue is different than drowsiness, according to The National Institutes of Health. Drowsiness is a feeling needing to sleep, but fatigue may not be relieved by rest. Fatigue may be caused by simple overexertion or stress, but can also be caused by underlying medical conditions, some of which are serious and life-threatening. Because fatigue can be so nonspecific, doctors may find it difficult to treat and many people never find adequate help. Many different conditions can cause fatigue.
Cancer
According to the National Cancer Institute, fatigue occurs in up to 96% of all people who have cancer, especially those who are receiving treatment for their cancer. Cancer can cause fatigue in many different ways, such as with a tumor spreading to bone marrow and causing anemia, or by forming toxic chemicals and directly affecting cellular function. Many people initially seek treatment for fatigue and find out later that they have cancer. Extreme and unrelenting fatigue can be a serious sign and should be investigated by a doctor.
Anemia
Red blood cells deliver oxygen to the tissues of the body, and hemoglobin is a protein within the red blood cells that binds the oxygen and helps transport it. Anemia is characterized by too little hemoglobin, and therefore insufficient amounts of oxygen are able to be delivered to the body. Because of the lack of oxygen, metabolic processes cannot continue at the rate necessary, causing fatigue. Anemia can be a symptom of another underlying condition such as cancer, rheumatoid arthritis, bone marrow disease, loss of blood or immune problems.
Chronic Fatigue Syndrome
According to the Centers for Disease Control and Prevention, between 1 and 4 million Americans suffer with chronic fatigue syndrome, many of whom are unemployed and seriously impaired. The official definition of chronic fatigue syndrome includes the parameter that the patient must have severe chronic fatigue for six months in duration without any other identifiable medical conditions. In addition, chronic fatigue must be accompanied by other symptoms, such as joint pain, short-term memory loss, sore throat, tender lymph nodes, and unrefreshing sleep. There are no prescription drugs that have been developed for chronic fatigue, and treatment revolves around attempting to change lifestyle and treat symptoms.
Heart Disease
In many patients with heart disease, the heart is unable to efficiently pump sufficient amounts of oxygen-rich blood to the tissues, which results in fatigue. In many cases, patients with congestive heart failure and congenital defects experience extreme fatigue as the heart works inefficiently to pump blood.
Sleep Apnea
Individuals with sleep apnea are unable to get sufficient rest even when they spend large amounts of time in bed. Sleep apnea is a condition where the patient cannot get appropriate airflow through the air passages, which causes them to wake up periodically, gasping for air. Patients rarely realize they are waking up during the night. Sleep apnea can be a dangerous and life-threatening condition.
