context: Tiredness happens to everyone -- it is an expected feeling after certain activities or at the end of the day. Usually, you know why you are tired and a good night's sleep solves the problem. Fatigue, in contrast to tiredness, is a daily lack of energy, an unusual or excessive whole-body tiredness not relieved by sleep. It can be acute (lasting a month or less) or chronic (lasting from one month to six months or longer). Fatigue can prevent a person from functioning normally and impacts a person's quality of life. Fatigue is one of the most common side effects of cancer and its treatment. It is not predictable by tumor type, treatment, or stage of illness. Usually, it comes on suddenly, does not result from activity or exertion, and is not relieved by rest or sleep. It often is described as "paralyzing." It may continue even after treatment is complete. The exact reason is unknown. Cancer-related fatigue may be related to the disease process or its treatments. Cancer treatments commonly associated with fatigue include: Chemotherapy. Any chemotherapy drug may cause fatigue. Patients frequently experience fatigue after several weeks of chemotherapy, but this varies among patients. In some patients, fatigue lasts a few days, while in others, it persists throughout and after the treatment is complete. Radiation therapy. Radiation therapy can cause cumulative fatigue (fatigue that increases over time). This can occur regardless of the treatment site. Fatigue usually lasts from three to four weeks after treatment stops, but can continue for up to two to three months. Bone marrow transplantation. This aggressive form of treatment can cause fatigue that lasts up to one year. Biological therapy. Interferons and interleukins are cytokines, natural cell proteins that are normally released by white blood cells in response to infection. These cytokines carry messages that regulate other elements of the immune and endocrine systems. In high amounts, these cytokines can be toxic and lead to persistent fatigue. Combination or sequential therapy. More than one cancer treatment at the same time or one after the other increases the chances of developing fatigue. Other factors that may contribute to cancer-related fatigue include: Tumor-induced hypermetabolic state. Cancer cells compete with normal cells for nutrients, often at the expense of the normal cells' growth. In addition to fatigue, weight loss and decreased appetite are common effects of this condition. Decreased nutrition from the side effects of treatments (such as nausea, vomiting, mouth sores, taste changes, heartburn, or diarrhea) can cause fatigue. Anemia. Cancer treatments can cause reduced blood counts, which may lead to anemia, a blood disorder that occurs when there is not enough hemoglobin in the blood. Hemoglobin is a substance in the red blood cells that enables the blood to transport oxygen through the body. When the blood can't transport enough oxygen to the body, fatigue can result. Hypothyroidism. If the thyroid gland is under-active (hypothyroidism), metabolism may slow down so that the body does not burn food fast enough to provide adequate energy. This is a common condition in general, but may happen after radiation therapy to the lymph nodes in the neck or some targeted therapies. Symptoms include feeling cold and unexplained weight gain, in addition to severe fatigue. Medications. Medications used to treat side effects such as nausea, pain, depression, anxiety, and seizures, can cause fatigue. Pain. Research shows that chronic, severe pain increases fatigue. Stress. Stress can worsen feelings of fatigue. Stress can result from dealing with the disease and the "unknowns," as well as from worrying about daily accomplishments or trying to meet the expectations of others. Overworking yourself. Fatigue may result when patients try to maintain their normal daily routines and activities during treatments. Modification may be necessary in order to conserve energy. Depression. Depression and fatigue often go hand-in-hand. It may not be clear which started first. One way to sort this out is to try to understand your depressed feelings and how they affect your life. If you are depressed all the time, were depressed before your cancer diagnosis, are preoccupied with feeling worthless and useless, then you may need treatment for depression. Immobility can reduce endurance and decondition muscles. Hormonal changes, a side effect of cancer treatment or pain medication, can cause fatigue. Medications for other illnesses, and the illnesses themselves, may cause fatigue. A classic example are blood pressure medications. The best way to combat fatigue is to treat the underlying medical cause. Unfortunately, the exact cause often is unknown or there may be multiple causes. There are some medical treatments that may help improve fatigue caused by hypothyroidism or anemia. Other causes of fatigue must be managed on an individual basis. The following are tips you can use to combat fatigue. Evaluate your energy level. Think of your personal energy stores as a "bank." Deposits and withdrawals have to be made over the course of the day or the week to balance energy conservation, restoration and expenditure. Keep a diary for one week to identify the time of day when you are either most fatigued or have the most energy. Note what you think may be contributing factors. Be alert to the warning signs of fatigue. Fatigue warning signs may include tired eyes, tired legs, whole-body tiredness, stiff shoulders, decreased energy or a lack of energy, inability to concentrate, weakness or malaise, boredom or lack of motivation, sleepiness, increased irritability, nervousness, anxiety, or impatience. Plan ahead and organize your work. Change storage of items to reduce trips or reaching. Delegate tasks when needed. Combine activities and simplify details. Schedule times to rest. Balance periods of rest and work. Rest before you become fatigued. Remember that frequent, short rests are beneficial. Pace yourself. A moderate pace is better than rushing through activities. Alternate sitting and standing. Practice proper body mechanics. Alternate sitting with standing. When sitting, use a chair with good back support and sit up straight. Try to work without bending over. When bending to lift something, bend your knees and use your leg muscles, not your back, to lift. Carry several small loads instead of one large one, or use a cart. Limit work that requires reaching over your head. Use long-handled tools, store items lower and delegate activities. Limit work that increases muscle tension (isometric work). Breathe evenly. Do not hold your breath. Wear comfortable clothes to allow for free and easy breathing. Identify things in your environment that may cause fatigue. Avoid extremes of temperature. Eliminate smoke or harmful fumes. Avoid long, hot showers or baths. Prioritize your activities. Decide which activities are important to you, and what could be delegated. Use your energy on important tasks. Cancer-related fatigue is often made worse if you are not eating or drinking enough or if you are not eating the right foods. Maintaining good nutrition can help you feel better and have more energy. The following are strategies to help improve nutritional intake: Meet your basic calorie needs. The estimated calorie needs for someone with cancer is 15 calories per pound of weight if your weight has been stable. Add 500 calories per day if you have lost weight. Example: A person who weighs 150 lbs. needs about 2250 calories per day to maintain his or her weight; active people need 20 calories per pound of weight to maintain their body weight. Include protein in your diet. Protein rebuilds and repairs damaged (and normally aging) body tissue. The estimated protein needs are 0.5 to 0.6 grams of protein per pound of body weight. Example: A 150 lb. person needs 75 to 90 grams of protein per day; active people need 1-1.5 grams of protein per pound of body weight. The best sources of protein include foods from the dairy group (8 oz. milk = 8 grams protein) and meats (meat, fish, or poultry = 7 grams of protein per ounce). Drink plenty of fluids. A minimum of eight cups of fluid per day will prevent dehydration. ( That's 64 oz., 2 quarts or 1 half-gallon). Fluids can include juice, milk, broth, milkshakes, gelatin, and other beverages. Of course, water is fine, too. Beverages containing caffeine do NOT count. Keep in mind that you'll need more fluids if you have treatment side effects such as vomiting or diarrhea. In warm climates, 96 ounces of fluids should be the minimum daily intake. Make sure you are getting enough vitamins. Take a vitamin supplement if you are not sure you are getting enough nutrients. A recommended supplement would be a multivitamin that provides at least 100% of the recommended daily allowances ( RDA) for most nutrients. Note: vitamin supplements do not provide calories, which are essential for energy production. So vitamins cannot substitute for adequate food intake. Also, some doctors are strict about vitamin intake during chemotherapy so be sure to discuss what vitamins should be taken. Make an appointment with a dietitian. A registered dietitian provides suggestions to work around any eating problems that may be interfering with proper nutrition (such as early feeling of fullness, swallowing difficulty, or taste changes). A dietitian can also suggest ways to maximize calories and include proteins in smaller amounts of food (such as powdered milk, instant breakfast drinks, other commercial supplements, or food additives). Managing stress can play an important role in combating cancer and fatigue. The following are some suggestions to manage stress: Adjust your expectations. For example, if you have a list of ten things you want to accomplish today, pare it down to two and leave the rest for other days. A sense of accomplishment goes a long way to reducing stress. Help others understand and support you. Family and friends can be helpful if they can "put themselves in your shoes" and understand what fatigue means to you. Cancer support groups can be a source of support as well. Other people with cancer understand what you are going through. Relaxation techniques, such as audiotapes that teach deep breathing or visualization, can help reduce stress. Activities that divert your attention away from fatigue can also be helpful. For example, activities such as knitting, reading, or listening to music require little physical energy but require attention. If your stress seems out of control, talk to a health care professional. They are here to help. Although cancer-related fatigue is a common and an often expected side effect of cancer and its treatments, you should feel free to mention your concerns to your health care providers. There are times when fatigue may be a clue to an underlying medical problem. Other times, there may be medical interventions to assist in controlling some of the causes of fatigue. Finally, there may be suggestions that are more specific to your situation that would help in combating your fatigue. Be sure to let your doctor or nurse know if you have: Increased shortness of breath with minimal exertion Uncontrolled pain Inability to control side effects from treatments (such as nausea, vomiting, diarrhea, or loss of appetite) Uncontrollable anxiety or nervousness Ongoing depression