Chronic Fatigue – The Constant Battle

What are we calling fatigue these days?  Fibromyalgia?  Somnolence? Dyspnea? Exhaustion?  Chronic fatigue syndrome?

Since its importance is often underestimated in folks over 40 or so, patients with fatigue may not receive an intervention, potentially resulting in significant functional decline. This article discusses the importance of identifying the underlying etiology or etiologies of a patient’s fatigue so that it can be eliminated, if possible, or managed appropriately. History-taking, including consideration of the patient’s symptom severity, is the most important part of evaluating fatigue. The authors present an algorithm that can be used to help identify the cause of a patient’s fatigue.

Although fatigue is common among older people, it is frequently underreported and often not even evaluated because, much like pain, it is often identified by both the older individual and his or her family or caregiver(s) as a natural part of the aging process. A 2010 study measuring the degree of interference with walking, work, and social interactions due to pain and fatigue showed that healthcare professionals tended to give a low priority to evaluating older persons reporting fatigue; in contrast, patients rated fatigue as one of the most important symptoms needing to be evaluated.1

Another recent study, which compared patient self-reports of symptom severity with inferences made by nurses and caregivers in a hospital chemotherapy unit, showed that nurses tended to underestimate the patients’ degree of fatigue.2 Such discrepancies delay work-up and/or intervention; therefore, it is important that healthcare professions caring for older persons not ignore symptoms of fatigue. The often-confusing manner in which the patient may express the problem of fatigue can complicate its identification. Individuals with fatigue, for example, frequently report that they are “weak.” If weakness is ruled out by physical examination, reports of weakness should be equated with fatigue and approached accordingly.

Here I am presenting a basic overview of fatigue in the older patient, including a discussion of its definitions, epidemiology, classification, and impact on older adults. It also offers an algorithm that can be used to evaluate and correct the etiology or etiologies of fatigue.


There is no universally accepted definition of fatigue because the condition is a subjective sensation. The National Institutes of Health defines fatigue as a feeling of weariness, tiredness, or lack of energy, which is different from drowsiness—a feeling of needing sleep—in that there is marked lack of motivation in one’s daily activities. Drowsiness and apathy can be symptoms of fatigue.  One definition of fatigue requires the following characteristics: (1) an inability to initiate a normal activity due to perceived generalized weakness; (2) a reduced capacity to maintain activity (ie, easy fatigability); and (3) difficulty with concentration, memory, and emotional stability (ie, mental fatigability).

At times, individuals report feeling fatigued when, in fact, they have other issues affecting their daily lives, such as boredom, distaste for work, exhaustion, lack of energy, sleepiness, tiredness, dyspnea, or weakness.  While fatigue should be distinguished from symptoms of somnolence (ie, the quality or state of being drowsy), dyspnea (ie, difficult or labored respiration) and weakness, these symptoms may coexist with fatigue, especially in the older person, who is more likely to have multiple medical conditions. While there are many causes of dyspnea, such as chronic obstructive pulmonary disease (COPD) and congestive heart failure, fatigue itself is not associated with symptoms of dyspnea.  In addition, an undiagnosed sleep disorder, such as narcolepsy or obstructive sleep apnea, may contribute to a patient’s fatigue.

The current prevalence of fatigue in the US older adult population is not known because varying definitions of fatigue have been used in clinical studies.  However, population-based surveys from Britain and the United States have estimated the prevalence of fatigue to be between 6.0% and 7.5%, respectively.  An estimated 21% to 33% of patients who seek medical attention in primary care settings report having significant fatigue; further, symptoms of fatigue account for approximately 7 million office visits per year in the United States, with the majority of these patients being women.

Fatigue may be categorized by its duration of symptoms (eg, recent [<1 month], prolonged [1-6 months], or chronic [>6 months]).4,9 Chronic fatigue may result from any number of causes that have evaded diagnosis and have continued without treatment for a prolonged period of time.

In the absence of one of these causes, it may be identified as idiopathic chronic fatigue. Chronic fatigue syndrome has specific diagnostic criteria as defined by the Centers for Disease Control and Prevention (CDC) and should not be used to describe fatigue that does not have a specifically identified cause.  Refer to the section below on chronic fatigue syndrome for detailed information on diagnosis.


Fatigue is of particular interest to researchers focused on geriatric and disability issues. This is not surprising when one considers the impact that this symptom has on middle-aged and older adults, especially those with medical disabilities. Self-reported fatigue has been associated with a worsening or altering of all of the following:

Physical function: reduced activities, prolonged periods of rest, uncoordinated movements, increased risk of falling, and increased need for assistance to meet basic activities of daily living and instrumental activities of daily living;

Cognition: reduced alertness, decreased concentration, reduced clarity of thoughts, and increased forgetfulness;

Emotional state: increased anger, emotional lability, and depression; and

Social isolation: complete or near-complete lack of contact with other persons.

In addition, fatigue is an independent predictor of mortality and has been associated with a significant reduction in overall functional status.

If YOU are feeling what I am feeling, what so many of my friends are feeling, don’t walk–RUN to your doctor and try to come up with a diagnosis–it could VASTLY improve the quality of your life going forward.