side effect can reassure the patient. Up to 25% of cancer patients will experience depression. Sleep disturbances: Patients who do not sleep well are more tired than others. Cancer patients commonly experience insomnia or hypersomnia. Sleep disturbances may be caused by sleeping too much during the day, by restless leg syndrome, by pain, by anxiety, or by other medical conditions, like obstructive sleep apnea or menopause. Practicing good sleep hygiene may reduce fatigue by improving sleep quality. Nutritional disturbances: Patients may have difficulty eating, may not be absorbing food well, or may have chosen an extreme diet as an alternative cancer treatment. Loss of appetite, diarrhea and vomiting may result in the patient consuming too few calories or becoming dehydrated. Lack of physical activity: Decreased physical activity can make fatigue worse by reducing endurance and muscle strength. Participating in regular aerobic and muscle-strengthening physical activity both during and after cancer treatment may reduce cancer-related fatigue. Current physical activity guidelines recommend adults with cancer to engage in at least 150 minutes per week of moderate- intensity or 75 minutes per week of vigorous-intensity aerobic physical activity, or an equivalent combination. It is also recommended to perform muscle-strengthening physical activity two to three times a week, although there are studies showing that aerobic training is better at mitigating symptoms of cancer-related fatigue and reduces the risk of post exercise malaise. Physical activities should be tailored to individual needs and physical abilities. Side effects from medications: Fatigue and sleepiness are known side effects with some kinds of medications. Sometimes a change of medication, the dose, or the timing of the medication may result in less fatigue. For example, an antihistamine might be taken shortly before sleep, rather than in the middle of the day. Substance abuse: Alcohol, marijuana, and many other drugs can produce fatigue as a side effect. Other medical conditions: Cancer and its treatment usually put intense physical stress on the body, which can exacerbate other medical conditions. Additionally, fatigue may result from an infection. Prognosis Fatigue caused by the cancer or its treatment often resolves if treatment is successful. However, some patients experience long-term or chronic fatigue. When strict definitions are used, about 20% of long-term, disease-free cancer survivors report fatigue. Under looser definitions, up to half of cancer survivors report fatigue. However, these studies are largely limited to patients with breast cancer, or peripheral stem cell transplant or bone