Fatigue

Definition

Fatigue is physical and/or mental exhaustion that can be triggered by stress, medication, overwork, or mental and physical illness or disease.

Description

Everyone experiences fatigue occasionally. It is the body's way of signaling its need for rest and sleep. But when fatigue becomes a persistent feeling of tiredness or exhaustion that goes beyond normal sleepiness, it is usually a sign that something more serious is amiss.

Physically, fatigue is characterized by a profound lack of energy, feelings of muscle weakness, and slowed movements or central nervous system reactions. Fatigue can also trigger serious mental exhaustion. Persistent fatigue can cause a lack of mental clarity (or feeling of mental "fuzziness"), difficulty concentrating, and in some cases, memory loss.

Causes and symptoms

Fatigue may be the result of one or more environmental causes such as inadequate rest, improper diet, work and home stressors, or poor physical conditioning, or one symptom of a chronic medical condition or disease process in the body. Heart disease, low blood pressure, diabetes, end-stage renal disease, iron-deficiency anemia, narcolepsy, and cancer can cause long-term, ongoing fatigue symptoms. Acute illnesses such as viral and bacterial infections can also trigger temporary feelings of exhaustion. In addition, mental disorders such as depression can also cause fatigue.

A number of medications, including antihistamines, antibiotics, and blood pressure medications, may cause drowsiness as a side-effect. Individuals already suffering from fatigue who are prescribed one of these medications may wish to check with their healthcare provider about alternative treatments.

Extreme fatigue which persists, unabated, for at least six months, is not the result of a diagnosed disease or illness, and is characterized by flu-like symptoms such as swollen lymph nodes, sore throat, and muscle weakness and/or pain may indicate a diagnosis of chronic fatigue syndrome. Chronic fatigue syndrome (sometimes called chronic fatigue immune deficiency syndrome), is a debilitating illness that causes overwhelming exhaustion and a constellation of neurological and immunological symptoms. Between 1.5 and 2 million Americans are estimated to suffer from the disorder.

Diagnosis

Because fatigue is a symptom of a number of different disorders, diseases, and lifestyle choices, diagnosis may be difficult. A thorough examination and patient history by a qualified healthcare provider is the first step in determining the cause of the fatigue. A physician can rule out physical conditions and diseases that feature fatigue as a symptom, and can also determine if prescription drugs, poor dietary habits, work environment, or other external stressors could be triggering the exhaustion. Several diagnostic tests may also be required to rule out common physical causes of exhaustion, such as blood tests to check for iron-deficiency anemia.

Diagnosis of chronic fatigue syndrome is significantly more difficult. Because there is no specific biological marker or conclusive blood test to check for the disorder, healthcare providers must rely on the patient's presentation and severity of symptoms to make a diagnosis. In many cases, individuals with chronic fatigue syndrome go through a battery of invasive diagnostic tests and several years of consultation with medical professionals before receiving a correct diagnosis.

Treatment

Conventional medicine recommends the dietary and lifestyle changes outlined above as a first line of defense against fatigue. Individuals who experience occasional fatigue symptoms may benefit from short term use of caffeine-containing central nervous stimulants, which make people more alert, less drowsy, and improve coordination. However, these should be prescribed with extreme caution, as overuse of the drug can lead to serious sleep disorders, like insomnia.

Another reason to avoid extended use of caffeine is its associated withdrawal symptoms. People who use large amounts of caffeine over long periods build up a tolerance to it. When that happens, they have to use more and more caffeine to get the same effects. Heavy caffeine use can also lead to dependence. If an individual stops using caffeine abruptly, withdrawal symptoms may occur, including headache, fatigue, drowsiness, yawning, irritability, restlessness, vomiting, or runny nose. These symptoms can go on for as long as a week.

Alternative treatment

The treatment of fatigue depends on its direct cause, but there are several commonly prescribed treatments for non-specific fatigue, including dietary and lifestyle changes, the use of essential oils and herbal therapies, deep breathing exercises, traditional Chinese medicine, and color therapy.

Dietary changes

Inadequate or inappropriate nutritional intake can cause fatigue symptoms. To maintain an adequate energy supply and promote overall physical well-being, individuals should eat a balanced diet and observe the following nutritional guidelines:

• Drinking plenty of water. Individuals should try to drink 9 to 12 glasses of water a day. Dehydration can reduce blood volume, which leads to feelings of fatigue.
• Eating iron-rich foods (i.e., liver, raisins, spinach, apricots). Iron enables the blood to transport oxygen throughout the tissues, organs, and muscles, and diminished oxygenation of the blood can result in fatigue.
• Avoiding high-fat meals and snacks. High fat foods take longer to digest, reducing blood flow to the brain, heart, and rest of the body while blood flow is increased to the stomach.
• Eating unrefined carbohydrates and proteins together for sustained energy.
• Balancing proteins. Limiting protein to 15-20 grams per meal and two snacks of 15 grams is recommended, but not getting enough protein adds to fatigue. Pregnant or breastfeeding women should get more protein.
• Getting the recommended daily allowance of B complex vitamins (specifically, pantothenic acid, folic acid, thiamine, and vitamin B₁₂). Deficiencies in these vitamins can trigger fatigue.
• Getting the recommended daily allowance of selenium, riboflavin, and niacin. These are all essential nutritional elements in metabolizing food energy.
• Controlling portions. Individuals should only eat when they're hungry, and stop when they're full. An overstuffed stomach can cause short-term fatigue, and individuals who are overweight are much more likely to regularly experience fatigue symptoms.

Lifestyle changes

Lifestyle factors such as a high-stress job, erratic work hours, lack of social or family support, or erratic sleep patterns can all cause prolonged fatigue. If stress is an issue, a number of relaxation therapies and techniques are available to help alleviate tension, including massage, yoga, aromatherapy, hydrotherapy, progressive relaxation exercises, meditation, and guided imagery. Some individuals may also benefit from individual or family counseling or psychotherapy sessions to work through stress-related fatigue that is a result of family or social issues.

Maintaining healthy sleep patterns is critical to proper rest. Having a set "bedtime" helps to keep sleep on schedule. A calm and restful sleeping environment is also important to healthy sleep. Above all, the bedroom should be quiet and comfortable, away from loud noises and with adequate window treatments to keep sunlight and streetlights out. Removing distractions from the bedroom such as televisions and telephones can also be helpful.

Essential oils

Aromatherapists, hydrotherapists, and other holistic healthcare providers may recommend the use of essential oils of rosemary (Rosmarinus officinalis ), eucalyptus blue gum (Eucalyptus globulus ), peppermint, (Mentha x piperata ), or scots pine oil (Pinus sylvestris ) to stimulate the nervous system and reduce fatigue. These oils can be added to bathwater or massage oil as a topical application. Citrus oils such as lemon, orange, grapefruit, and lime have a similar effect, and can be added to a steam bath or vaporizer for inhalation.

Herbal remedies

Herbal remedies that act as circulatory stimulants can offset the symptoms of fatigue in some individuals. An herbalist may recommend an infusion of ginger (Zingiber officinale ) root or treatment with cayenne (Capsicum annuum ), balmony (Chelone glabra ), damiana (Turnera diffusa ), ginseng (Panax ginseng ), or rosemary (Rosmarinus officinalis ) to treat ongoing fatigue.

An infusion is prepared by mixing the herb with boiling water, steeping it for several minutes, and then removing the herb from the infusion before drinking. A strainer, tea ball, or infuser can be used to immerse loose herb in the boiling water before steeping and separating it. A second method of infusion is to mix the loose herbal preparation with cold water first, bringing the mixture to a boil in a pan or teapot, and then separating the tea from the infusion with a strainer before drinking.

Caffeine-containing central nervous system stimulants such as tea (Camellia senensis ) and cola (Cola nitida ) can provide temporary, short-term relief of fatigue symptoms. However, long-term use of caffeine can cause restlessness, irritability, and other unwanted side effects, and in some cases may actually work to increase fatigue after the stimulating effects of the caffeine wear off. To avoid these problems, caffeine intake should be limited to 300 mg or less a day (the equivalent of 4-8 cups of brewed, hot tea).

Traditional Chinese medicine

Chinese medicine regards fatigue as a blockage or misalignment of qi, or energy flow, inside the human body. The practitioner of Chinese medicine chooses acupuncture and/or herbal therapy to rebalance the entire system. The Chinese formula Minot Bupleurum soup (or Xiao Chia Hu Tang) has been used for nearly 2,000 years for the type of chronic fatigue that comes after the flu. In this condition, the person has low-grade fever, nausea, and fatigue. There are other formulas that are helpful in other cases. Acupuncture involves the placement of a series of thin needles into the skin at targeted locations on the body known as acupoints in order to harmonize the energy flow within the human body.

Deep breathing exercises

Individuals under stress often experience fast, shallow breathing. This type of breathing, known as chest breathing, can lead to shortness of breath, increased muscle tension, inadequate oxygenation of blood, and fatigue. Breathing exercises can both improve respiratory function and relieve stress and fatigue.

Deep breathing exercises are best performed while laying flat on the back on a hard surface, usually the floor. The knees are bent, and the body (particularly the mouth, nose, and face) is relaxed. One hand should be placed on the chest and one on the abdomen to monitor breathing technique. With proper breathing techniques, the abdomen will rise further than the chest. The individual takes a series of long, deep breaths through the nose, attempting to raise the abdomen instead of the chest. Air is exhaled through the relaxed mouth. Deep breathing can be continued for up to 20 minutes. After the exercise is complete, the individual checks again for body tension and relaxation. Once deep breathing techniques have been mastered, an individual can use deep breathing at any time or place as a quick method of relieving tension and preventing fatigue.

Color therapy

Color therapy, also known as chromatherapy, is based on the premise that certain colors are infused with healing energies. The therapy uses the seven colors of the rainbow to promote balance and healing in the mind and body. Red promotes energy, empowerment, and stimulation. Physically, it is thought to improve circulation and stimulate red blood cell production. Red is associated with the seventh chakra, located at the root; or base of spine. In yoga, the chakras are specific spiritual energy centers of the body.

Therapeutic color can be administered in a number of ways. Practitioners of Ayurvedic, or traditional Indian medicine, wrap their patients in colored cloth chosen for its therapeutic hue. Individuals suffering from fatigue would be wrapped in reds and oranges chosen for their uplifting and energizing properties. Patients may also be bathed in light from a color filtered light source to enhance the healing effects of the treatment.

Individuals may also be treated with color-infused water. This is achieved by placing translucent red colored paper or colored plastic wrap over and around a glass of water and placing the glass in direct sunlight so the water can soak up the healing properties and vibrations of the color. Environmental color sources may also be used to promote feelings of stimulation and energy. Red wall and window treatments, furniture, clothing, and even food may be recommended for their energizing healing properties.

Color therapy can be used in conjunction with both hydrotherapy and aromatherapy to heighten the therapeutic effect. Spas and holistic healthcare providers may recommend red color baths or soaks, which combine the benefits of a warm or hot water soak with energizing essential oils and the fatigue-fighting effects of bright red hues used in color therapy.

Prognosis

Fatigue related to a chronic disease or condition may last indefinitely, but can be alleviated to a degree through some of the treatment options outlined here. Exhaustion that can be linked to environmental stressors is usually easily alleviated when those stressors are dealt with properly.

There is no known cure for chronic fatigue syndrome, but steps can be taken to lessen symptoms and improve quality of life for these individuals while researchers continue to seek a cure.

Prevention

Many of the treatments outlined above are also recommended to prevent the onset of fatigue. Getting adequate rest and maintaining a consistent bedtime schedule are the most effective ways to combat fatigue. A balanced diet and moderate exercise program are also important to maintaining a consistent energy level.

Resources

BOOKS

Davis, Martha, et al. The Relaxation & Stress Reduction Workbook. 4th ed. Oakland, CA: New Harbinger Publications, Inc., 1995.

Hoffman, David. The Complete Illustrated Herbal. New York: Barnes & Noble Books, 1999.

KEY TERMS

Aromatherapy— The therapeutic use of plantderived, aromatic essential oils to promote physical and psychological well-being.

Guided imagery— The use of relaxation and mental visualization to improve mood and/or physical well-being.

Hydrotherapy— Hydrotherapy, or water therapy, is use of water (hot, cold, steam, or ice) to relieve discomfort and promote physical well-being.

Fatigue

BIBLIOGRAPHY

Fatigue is an experienced state of discomfort, aversion, and inability to perform, otherwise known as tiredness or weariness (Bartley 1943; Bartley & Chute 1947). The term applies to the total individual (the organism-as-a-person) and not properly to an organ or tissue. Fatigue is to be distinguished from impairment, which refers to the inability of cells or tissues to perform. Fatigue is sometimes confused with work decrement, for quite often the inquirer is actually interested in work output rather than in the state of the performer.

Fatigue is brought about in various ways, one common cause being discomfort in muscles induced by exertion, another being impairment. Very often, however, fatigue arises from some sort of disorganization within the individual. This is induced, in part, through confrontation with circumstances that are disliked or considered futile and useless. The disorganization referred to here can be described at various body-process levels. Disorganization can involve a disruption in the proper timing of various processes or a conflict between these processes with subsequent tension, awkwardness, and forgetfulness that result in discomfort and the realization of inadequacy.

Chronic fatigue often represents an unwholesome outlook on daily routine or life in general or arises from personality disorganization rather than some debilitating body processes at a lower level (Muncie 1941).

Critique of common conceptions . The common outlook that confuses fatigue with impairment is characterized by several points, some of which are acceptable and some not (Bartley 1951). First is the view that activity modifies the acting system, and that the modification is a chemical one. Fatigue is taken to be such a modification. However, this is really impairment and is a phenomenon that takes place at the tissue level, whereas fatigue is a phenomenon at the personality level–the experience, the self-awareness of condition. It is also assumed that fatigue can be either a general body condition or specifically localized. The slowing down of a process is taken to be the evidence of fatigue or, by some writers, to be fatigue itself. Here again, it seems to be impairment that is at issue.

Conventional assumptions shift from considering fatigue as tissue effects to considering it as the way the organism-as-a-person behaves. Even at this level compensation is generally overlooked in human performance. This is evidenced in the tacit assumption made by many that the subject has only one way of performing a given task. For example, it is not presumed that one muscle fiber group may be recovering while some other group is taking its place in carrying on over-all performance. But this type of compensation does occur, and it makes many of the simple, customarily performed “fatigue” experiments inappropriate and inadequate.

It is also false to assume that fatigue developed in one kind of performance may be measured by using an altogether different performance as a test.

The concern with fatigue as distinct from work output arises most directly and forcefully in medical practice and is even encountered in athletics. Physicians are being constantly confronted with patients who complain of tiredness, sometimes in connection with convalescence from debilitating disease or simply as a syndrome of its own (Alvarez 1941; Harms & Soniat 1952; Muncie 1941). On the other hand, work output is generally the main concern in industry (Dill et al. 1936; Edwards et al. 1935). Fatigue is often a term incorrectly inferred when an individual notices certain symptoms. In this case, what is called fatigue is self-diagnosis rather than something that arises as a directly felt inability to perform. Thus, a patient may tell an ophthalmologist that he has visual fatigue, inferring this (a self-diagnosis) from the fact that after reading awhile what he sees becomes blurred. This is different than his reporting how he feels. Such a usage of fatigue is to be avoided if the language on fatigue is to be consistent.

Finally, according to the conventional view, there are several kinds of fatigue. The more basic categorization distinguishes objective fatigue (work decrement); subjective fatigue (the experience of tiredness); and physiological fatigue (change or reduction in a specific body process).

Although there are various additionally specified kinds of fatigue, when fatigue exists it is essentially the same in all cases. The core of fatigue is the self-realization of relative inability to carry on. It is a negative orientation toward a task demand. Although the stance toward demand is always essentially the same, various fringe details (various sensory and other components) may vary from case to case, but they are mere details in the unique over-all syndrome that is distinguishable as fatigue.

For example, fatigue arising in intellectual tasks should not be called mental fatigue, if by that one means a special kind of fatigue. Mental fatigue is only the fatigue that arises in intellectual (mental) tasks. Despite the fact that many kinds of tasks may lead to fatigue, no implication that there are many kinds of fatigue should be made.

So many loosely related phenomena have been called fatigue that it has been suggested that the word be done away with entirely (Muscio 1921). Bartley and colleagues (Bartley 1943; 1951; 1957; Bartley & Chute 1945; 1947) have chosen rather to retain the word in its original meaning (i.e., for the phenomena first labeled “tiredness”) and rename other phenomena associated with it.

Problems in studying fatigue . Many studies that are meant to be studies of fatigue begin with questions about the experience of tiredness and inability to continue performance and end up by bypassing these questions and by providing information about other problems. For example, an investigator may note that workers in a plant feel sluggish and ineffective during mid-morning and mid-afternoon. He may suppose that this has something to do with blood sugar level. In his study he finds that at these times blood sugar level is lowest. He may then try a plan whereby the workers take in the same total amount of food per day but eat varying numbers of meals. Some eat two, some three, some four, and some even five meals per day. Blood sugar level is then tested periodically throughout the day. It is found that where many meals are eaten the blood sugar level never falls as low at any part of the work day as it does when few meals are eaten. At this point, the investigator assumes his study is completed. He should continue and determine whether the feeling of sluggishness is eliminated or greatly reduced by redistributing food intake into a greater number of meals, with the total intake held constant. It is only when he has performed this additional step that the original questions of sluggishness and inefficiency receive an answer. It is only then that the investigation becomes a fatigue investigation.

One of the persistent problems in dealing with fatigue is its measurement. It is always expected that if an entity exists it can be measured. The definition of fatigue as a relation to demand in which the individual feels his own inability to go on makes easy measurement unattainable. When work output is all that is to be measured, such measurement is easily made. However, the problem of measuring fatigue as defined here is no different from the problem of measuring anxiety, depression, boredom, hope, anger, or a virtually uncountable number of other states of the organ-ism-as-a-person. Thus, the concept of fatigue should not be singled out for criticism because it refers to a phenomenon difficult to quantify. Nevertheless, such criticism has been leveled, at times, against what is conventionally called “subjective fatigue,” for that reason.

The first point to be recognized is that the phenomenon in question must exist in order to be measured or dealt with in any way. The first step in studying it is to produce it. The second is to manipulate conditions under which it occurs. The next point to realize is that the person fatigued is the only one able to state when it exists. The observations made by all others have to do with overt performance, body process, or both, which are not fatigue although they may be closely related to it in some way. It is also to be recognized that the problem of quantitatively dealing with fatigue involves either developing a fatigue scale or choosing a fatigue point, such as the point at which the performer is no longer able to continue.

It will become quickly evident that in most cases the crucial conditions that lead to fatigue lie within the subject himself rather than the external conditions that produce the demand. Whatever is done to study fatigue, the organism-centered approach is necessary. In fact, it is necessary in trying to understand work output as well.

In certain ways, the phenomena that are per-sonalistic rather than environmental can be studied more concretely than might be supposed. For example, it certainly is possible to manipulate goals (which are personalistic phenomena). In setting a task for a subject one can tell him something that will indicate the amount of time required to perform the task. One can then vary the amount of time so indicated to see what remoteness of goals has to do with the self-assessments of the subjects at various moments during performance and whether this variable has anything to do with the point at which “exhaustion” is reached. Other such dimensions and their body-process concomitants can also be chosen.

Another problem in studying fatigue has to do with how far various subjects will push themselves either in their use of energy resources or in experiencing bodily discomfort. This problem is related to motivation, and its solution may actually be a way of dealing with or measuring motivation. This problem is encountered not only in psychological experimentation but also in the physiological treadmill experiments. Some subjects “reach their limits” in muscular exertion before oxygen debt occurs, while others do not. No physiologist would expect that a subject would be exhausted before oxygen debt appears. These results illustrate the difference in the amount that individuals will push themselves. Thus the problem of subjectivity is as inherent in many phases of physiology as in psychology. Hence it cannot be disposed of by assuming that it occurs only in nonbehavioristic types of research.

Relieving fatigue. Various drugs and other substances have been tried by investigators to relieve fatigue and improve performance in athletic activities (Karpovich 1959; Smith & Beecher 1959).

Fatigue may often be relieved by inducing a change of attitude or attention or by shifting from one task to another rather than by rest (inactivity). Supposedly the needed change involves reorganization within the individual rather than a replenishment of energy.

Fatigue and the syndrome called stress by Selye (1956) have a lot in common, particularly certain factors of origin. Selye’s discoveries and concepts go a long way toward providing a bodily basis for human incapacity, and when this is coupled with a monistic psychology, which attempts to understand human behavior, considerable progress seems to be possible.

S. Howard Hartley

[Other relevant material may be found inACHIEVEMENT MOTIVATION; INFANCY, article OnTHE EFFECTS OF EARLY EXPERIENCE; SLEEP; STRESS.]

BIBLIOGRAPHY

ALVAREZ, W. C. 1941 What Is the Matter With the Patient Who Is Chronically Tired? Journal of the Missouri State Medical Association38 : 365–368.

HARTLEY, S. HOWARD 1943 Conflict, Frustration and Fatigue. Psychosomatic Medicine5 : 160–163.

BARTLEY, S. HOWARD 1951 Fatigue and Efficiency. Pages 318-347 in Harry Helson (editor), Theoretical Foundations of Psychology. New York: Van Nostrand.

HARTLEY, S. HOWARD 1957 Fatigue and Inadequacy. Physiological Reviews37 : 301–324.

HARTLEY, S. HOWARD; and CHUTE, ELOISE 1945 A Preliminary Clarification of the Concept of Fatigue. Psy-chological Review52 : 169–174.

HARTLEY, S. HOWARD; and CHUTE, ELOISE 1947 Fatigue and Impairment in Man. New York: McGraw-Hill.

DILL, D. B. et al. 1936 Industrial Fatigue. Journal of Industrial Hygiene and Toxicology18 : 417–431.

EDWARDS, H. T.; THORNDIKE, A.; and DILL, D. B. 1935 The Energy Requirement in Strenuous Muscular Exercise. New England Journal of Medicine213 : 532–535.

HARMS, H. E.; and SONIAT, T. L. L. 1952 The Meaning of Fatigue. Medical Clinics of North America36 : 311–317.

KARPOVICH, P. V. 1959 Effect of Amphetamine Sulfate on Athletic Performance. Journal of the American Medical Association170 : 558–561.

Muncie, Wendell 1941 Chronic Fatigue. Psychosomatic Medicine3 : 277–285.

Muscio, B. 1921 Is a Fatigue Test Possible? British Journal of Psychology12 : 31–46.

Selye, Hans 1956 The Stress of Life. New York: McGraw-Hill.

SMITH, G. M.; and BEECHER, H. K. 1959 Amphetamine Sulfate and Athletic Performance. Journal of the American Medical Association170:542–557.

Whiting, Helen F.; and ENGLISH, HORACE B. 1925 Fatigue Tests and Incentives. Journal of Experimental Psychology8 : 33–49.

Fatigue

Description

Fatigue is a feeling of exhaustion or loss of strength. The duration of fatigue for a patient with cancer has been found to last from one to two times the length of time between diagnosis and completion of treatment, so it is common for fatigue to persist beyond a patient's treatment regimen.

Causes

Many people experience fatigue as a side effect of cancer treatment. Both chemotherapy and radiation therapy are associated with fatigue. Scientists believe fatigue also occurs because the body is devoting so much of its energy fighting the cancer that it has little left over for daily life. Often the feelings of exhaustion are more intense immediately following a cancer treatment, but they gradually ease over time as the body gains strength.

During chemotherapy, anti-cancer drugs kill both cancer cells and healthy cells, including red blood cells. This can lead to anemia , or low red blood cell counts, which causes fatigue. Chemotherapy agents also attack white blood cells, weakening the immune system.

Medications, pain, depression , and the stress of the diagnosis and treatment are other factors that result in fatigue.

Treatments

If anemia is a problem, physicians may prescribe iron supplements or drugs, such as erythropoietin , to stimulate blood cell growth. In some cases, blood transfusions may be necessary.

Many people with cancer find that they must pace themselves, alternating periods of activity with small naps. Going to bed earlier also seems to help.

Research has shown that people who exercise experience less cancer-related fatigue. Walking or using an exercise bicycle are good choices. For those who have severe weakness, even a few minutes of gentle stretching in bed can make a difference.

Eating nutritious food is another way to get an energy boost to better fight cancer. Include a variety of fruits and vegetables, whole grains and plenty of protein, if nausea and vomiting are not a problem. High-calorie liquid meals can help offset severe weight loss for those who cannot tolerate solid foods. Drinking plenty of water also helps prevent diarrhea and dehydration, which add to fatigue.

Alternative and complementary therapies

Yoga has proven to be highly effective in reducing stress, thereby increasing energy and helping people to relax and sleep better.

Marijuana has been used to help ease nausea in cancer patients. Since a loss of appetite can cause weakness and fatigue, marijuana may help indirectly. Most states do not permit the use of marijuana for medical reasons. Physicians will be aware of these regulations.

Other complementary therapies, such as massage, aromatherapy, meditation, or prayer, help people with cancer relax, easing their worries and ultimately combatting fatigue.

See Also Complementary cancer therapies

Resources

BOOKS

Clegg, Holly B., and Gerald Miletello, MD. Eating Well Through Cancer. Baton Rouge: Holly B. Clegg Inc., 2001.

Hassett Dahm, Nancy, and Robert Schirmer. Mind, Body and Soul: A Guide to Living with Cancer. New York: Taylor Hill Publishing, 2000.

PERIODICALS

Dimeo, F. C. et al. "Effects of Physical Activity on the Fatigue and Psychologic Status of Cancer Patients During Chemotherapy." Cancer 85, no. 10 (May 15, 1999): 2273-7.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road, Atlanta, GA30329. (800) ACS-2345. <http://www.cancer.org>. CancerFatigue.org. Oncology Nursing Society, 501 HolidayDr., Pittsburgh, PA 15220. (412) 921-7373. <http://www.cancerfatigue.org>.

OTHER

"Fatigue." American Cancer Society June 2001. 28 June 2001<http://www3.cancer.org/cancerinfo/>.

Melissa Knopper, M.S.

KEY TERMS

Anemia

—A condition that occurs when the body has low red blood cell counts. It can cause fatigue.

Erythropoietin

—A drug used to stimulate blood cell growth when a person has anemia.

fa·tigue / fəˈtēg/ • n. 1. extreme tiredness, typically resulting from mental or physical exertion or illness: he was nearly dead with fatigue. ∎  a reduction in the efficiency of a muscle or organ after prolonged activity. ∎  weakness in materials, esp. metal, caused by repeated variations of stress: metal fatigue. ∎  a lessening in one's response to or enthusiasm for something, typically as a result of overexposure to it: museum fatigue. 2. (also fa·tigue de·tail) a group of soldiers ordered to perform menial, nonmilitary tasks, sometimes as a punishment. ∎  (fatigues) loose-fitting clothing, typically khaki, olive drab, or camouflaged, of a sort worn by soldiers: battle fatigues. • v. (-tigues , -tigued , -ti·guing ) [tr.] (often be fatigued) cause (someone) to feel tired or exhausted: they were fatigued by their journey. ∎  reduce the efficiency of (a muscle or organ) by prolonged activity. ∎  weaken (a material, esp. metal) by repeated variations of stress.

fatigue in engineering, microscopic cracking of materials, especially metals, after repeated applications of stress. Fissures may be formed within pieces of metal during their manufacture when, while cooling from the molten state, they shrink and tensile stresses arise. Once a crack has started it spreads under repeated stress until the metal ruptures. Examples of fatigue are found in steel rails, beams, and girders. Metallic fatigue resulted in the catastrophes encountered by many of the Liberty ships built during World Wars I and II and the crashes of a number of the earliest jet aircraft constructed. Materials used in construction are tested for fatigue strength, or endurance limit, by being subjected mechanically to cyclic applications of stress. Steel parts are sometimes treated by shot blasting to increase their fatigue resistance.

fatigue n.
1. (fatigues) loose-fitting clothing, typically khaki, olive drab, or camouflaged, of a sort worn by soldiers when performing such menial tasks or on active duty: battle fatigues.

2. (fatigues) a menial task of a nonmilitary nature performed by a soldier, sometimes as a punishment: we're on cookhouse fatigues, sir.

3. (fatigue party) a group of soldiers ordered to do such a duty.

4. weakness in materials, especially metal, caused by repeated variations of stress: metal fatigue.
v. weaken (a material, especially metal) by repeated variations of stress.

fatigue (fă-teeg) n.
1. mental or physical tiredness, following prolonged or intense activity. Muscle fatigue may be due to the waste products of metabolism accumulating in the muscles faster than they can be removed by the venous blood.

2. the inability of an organism, an organ, or a tissue to give a normal response to a stimulus until a certain recovery period has elapsed.

fatigue weariness; fatiguing duty or labour XVII (mil. sense XVIII). — F., f. (O)F, fatiguer vb. (whence fatigue vb. XVII) — L. fatīgāre exhaust, weary, f. *fatis in ad fatim, affatim abundantly, enough, prop. ‘to bursting’ (cf. fatiscāre, -ārī burst open, gape open).

154. Fatigue

See also 372. SLEEP .

hebetude

the state, condition, or quality of being dull, enervated, or lethargie. —hebetudinous , adj.

kopophobia

an abnormal fear of mental or physical exhaustion.

ponophobia

an abnormal fear of fatigue, especially through overworking.

fatigue A decline in the level of response of tissues (such as muscle), cells, etc., to nervous stimulation, which occurs after prolonged and continued stimulation of these structures.

fatigue See accommodation.

fatigue See ACCOMMODATION.

fatigue •fatigue, Grieg, intrigue, league, renege •colleague •Blitzkrieg, Sitzkrieg