Fatigue is a lack of energy or general feeling of tiredness. Fatigue affects almost everyone at some point. It is a common symptom of diabetes but can also be due to many other diseases and conditions. Additional causes include:
- Lack of sleep
- Physical exertion or inactivity
- Anxiety, depression or stress
- Cardiovascular conditions
- Certain medications
Though physicians and other medical professionals prefer the term fatigue, this condition can also be called tiredness, weariness, exhaustion or lethargy. It may be associated with a sudden increased need to rest or an inability to regain energy after periods of rest. Fatigue can affect individuals in many ways, including hindering concentration, impairing memory and causing accidents.
Fatigue can be acute or long term (chronic) in duration. Individuals who experience severe, persistent and often debilitating fatigue for six months or longer may suffer from a condition called chronic fatigue syndrome (CFS) or another underlying medical condition. If fatigue exceeds two weeks and has no obvious cause, individuals should seek immediate medical care.
There are no specific medical tests for measuring fatigue. However, the physician will typically perform a physical examination, including various tests to identify any underlying medical causes of fatigue.
Fatigue that is caused by behavioral and psychological factors can generally be treated and prevented by modifying certain lifestyle factors such as activity level and exercise. However, individuals whose fatigue is caused by disease may require medications or other interventions to treat the underlying condition.
Fatigue can be defined as a lack of energy or general feeling of tiredness. It is a predominant symptom of many medical conditions, including endocrine disorders such as diabetes and hypothyroidism. It can also be a normal response to factors such as:
- Physical exertion
- Lack of sleep
- Anxiety, depression or stress
- Inactivity or boredom
- Poor eating habits
- Certain medications, such as antihypertensives (drugs used to treat high blood pressure)
Individuals who experience fatigue may report that they feel weak, tired, worn out, exhausted or lethargic. The condition may be associated with a sudden increased need to rest or an inability to regain energy following periods of rest.
Fatigue can impede normal functioning and interfere with an individual’s ability to go to work, concentrate in school, perform household chores, maintain relationships and derive pleasure from favorite activities. In addition, fatigue can:
- Trigger headaches
- Impair memory
- Induce muscle pain
- Cause accidents
The duration of fatigue varies by individual and generally depends on the cause. Fatigue can be acute, with symptoms appearing suddenly and lasting less than a month, or long term (chronic).
Individuals who experience severe, persistent and often debilitating fatigue that exceeds six months in duration may suffer from a condition called chronic fatigue syndrome (CFS). This controversial condition affects an estimated 500,000 Americans, according to the U.S. Centers for Disease Control and Prevention (CDC).
Fatigue and diabetes
Fatigue is often a symptom of diabetes. People with type 1 diabetes may experience fatigue because their bodies do not produce enough insulin, a hormone that regulates glucose (blood sugar). Insulin allows glucose to enter the cells, where it is converted into energy and used to fuel bodily processes. Without sufficient insulin stores, the body lacks energy and becomes fatigued.
People with type 2 diabetes may experience fatigue because they are prone to a condition called insulin resistance, which affects about 90 percent of individuals with type 2 diabetes. Insulin resistance occurs when the body is unable to detect or properly use insulin. Because the body is unable to convert glucose into energy, fatigue often results. Other forms of diabetes involving insulin resistance include gestational diabetes.
Many diabetic complications and conditions can cause fatigue as well. These include:
- Hypoglycemia (low blood glucose). When less glucose is available, the body is unable to produce sufficient energy to fuel the muscles and bodily processes. This results in feelings of tiredness or fatigue.
- Hyperglycemia (high blood glucose). Hyperglycemia occurs when the body has insufficient insulin or when the body cannot use insulin properly. As a result, elevated levels of glucose remain in the bloodstream instead of entering the cells and being converted to energy. Therefore, individuals with hyperglycemia often experience fatigue.
- Obesity. Most people with type 2 diabetes are overweight or obese. Excess weight reduces physical functioning, often reduces the desire to exercise and can be wearying.
- Diabetic ketoacidosis (a condition of severe hyperglycemia and buildup of ketones in the blood). Individuals with ketoacidosis often experience profound fatigue because their body does not have adequate insulin and therefore cannot use glucose for energy, and the buildup of ketones also disrupts basic bodily functions.
- Dehydration. A symptom of diabetes, dehydration can accompany hyperglycemia, polyuria, ketoacidosis and hyperosmolar hyperglycemia nonketotic syndrome. Lack of fluids impairs functioning throughout the body. In extreme cases, dehydration in association with elevated blood glucose levels can lead to diabetic coma.
- Autonomic neuropathy (damage to the autonomic nervous system, which controls involuntary functions such as digestion). Individuals with this form of diabetic neuropathy may experience low blood pressure (hypotension), which often produces feelings of fatigue.
- High blood pressure. Fatigue can accompany hypertension as well as hypotension.
- Coronary artery disease (CAD, characterized by hardening of the heart’s arteries). CAD is a type of heart disease that occurs when the coronary arteries become narrowed and clogged, restricting the flow of blood to the heart. Patients with CAD are likely to develop fatigue because their weakened heart muscle is unable to pump enough blood and oxygen to support regular body functions. Some heart medications and blood pressure medications (antihypertensives) may also cause fatigue.
- Heart failure. Individuals with heart failure are more prone to fatigue because a weakened heart muscle does not have the ability to pump sufficient blood and oxygen for normal body function. People with diabetes have an increased risk of CAD and heart failure. For more information, see Heart Conditions & Diabetes.
- Peripheral arterial disease (PAD). The American Diabetes Association estimates that one-third of diabetic individuals over age 50 have PAD, a disease state in which fatty plaque in the arteries (atherosclerosis) reduces blood flow, typically in the legs. Severe PAD can lead to the need for amputation of a lower limb.
- Kidney disease. Renal disorders such as diabetic nephropathy cause a buildup of waste products in the body and can cause anemia (decreased number of red blood cells). Kidney diseases and anemia are both generally accompanied by fatigue.
Other potential causes of fatigue
Causes of fatigue can be behavioral, psychological or biological. The origin of fatigue can therefore be difficult to diagnose. Behavioral causes of fatigue may include:
- Lack of sleep
- Poor diet
- Excessive consumption of alcohol or caffeine
- Drug abuse
Fatigue caused by these factors may subside naturally or with a few simple lifestyle changes, such as engaging in regular exercise or going to bed an hour earlier. Individuals may choose to keep a diary to help identify the time of day in which fatigue is most prevalent so they can adjust their schedule accordingly.
Psychological factors that can produce fatigue may include:
Though psychologically induced fatigue may also subside on its own, patients may benefit from mental-health counseling.
In addition to diabetes and its related conditions and complications, fatigue may be associated with numerous other disorders. These include:
- Sleep disorders such as insomnia, narcolepsy, night terrors and sleepwalking.
- Other conditions that disrupt sleep, such as apnea, flu, gastric reflux, restless legs syndrome, periodic limb movement disorder and diabetes insipidus.
- Autoimmune diseases such as lupus and rheumatoid arthritis. People with type 1 diabetes are at increased risk of having additional autoimmune disorders.
- Other forms of arthritis.
- Other chronic musculoskeletal conditions, including back pain, chronic fatigue syndrome, fibromyalgia, myositis, polymyalgia rheumatica and sarcoidosis.
- Allergies, asthma and respiratory disorders.
- Anemia and the hereditary blood disorder sickle cell anemia.
- Cancer. Cancer is often associated with weight loss and fatigue, and when this becomes severe is frequently termed inanition.
- Digestive disorders such as fatty liver (a disease sometimes caused by diabetes), hemochromatosis (excess absorption of iron, a risk factor for diabetes), hepatitis and inflammatory bowel disease.
- Endocrine disorders, including hypothyroidism (underactive thyroid gland) acromegaly (overproduction of growth hormone by the pituitary gland, a risk factor for diabetes), adrenal insufficiency (Addison’s disease) and hyperparathyroidism (overactive parathyroid glands).
- Infectious diseases such as HIV/AIDS, encephalitis and Lyme disease.
- Migraines and other headaches.
- Neurological diseases such as multiple sclerosis and polio.
- Gulf War syndrome.
In addition, many medications can cause fatigue, including antidepressants, antihistamines, antihypertensives, anticonvulsants, chemotherapy and other cancer treatments, and painkillers. Medications such as corticosteroids (a class of immunosuppressants) can lead to fatigue by interfering with sleep.
Diagnosis of fatigue
Individuals troubled by fatigue are advised to seek medical care, especially if fatigue is accompanied by any of the following symptoms:
- Sudden, unexplained weight loss or gain
- Dizziness or fainting
- Other symptoms that may indicate diabetes, such as excessive hunger (polyphagia), excessive thirst (polydipsia), excessive urination (polyuria), changes in mood or vision, itchy skin (pruritus), slow-healing wounds, or frequent yeast infections or other infections
- Abnormal bleeding
- Breathing difficulties
- Chest pain
- Severe headache
- New masses, lumps or bumps on the body
- Severe pain in the pelvis, abdomen or back
- Signs of severe illness (e.g., fever, nausea, vomiting)
- Similar symptoms in other household members or pets
At present, there are no specific medical tests for diagnosing fatigue. However, the physician will generally review the patient’s medical history and perform a physical examination as well as various tests to eliminate certain medical causes of fatigue, such as diabetes. The tests may include:
- Laboratory tests such as blood tests and urinalysis.
- X-rays. Use low doses of electromagnetic radiation to create images of body parts. X-rays can be used to diagnose a wide range of conditions, from bronchitis to a broken arm.
- Pulmonary function tests (PFT). Record a patient’s capacity to inhale (breathe in) and exhale (breathe out). PFTs measure several aspects of lung function to diagnose lung conditions.
- Electrocardiogram (ECG or EKG). Evaluates the status of the cardiac system by recording the electrical potential generated by the heart.
- CAT scan (computed axial tomography). Produces cross-sectional x-ray images of any number of body systems, including respiratory, neurological, gastrointestinal and musculoskeletal systems.
- MRI (magnetic resonance imaging). Produces cross-sectional images of the body and can “see through” bone and fluid-filled soft tissue.
Treatment and prevention of fatigue
Elevated glucose (blood sugar) is a common cause of fatigue in people with diabetes. Diabetic individuals can reduce the risk of developing fatigue by controlling their glucose through a physician-prescribed plan. A diabetes treatment plan typically features diet and exercise and may involve insulin and other diabetes medications.
People with and without diabetes can reduce the likelihood of developing fatigue with:
- Regular physical activity, but not within a few hours before bedtime
- Proper nutrition
- Achieving a desirable body weight
- Adequate, regular sleep
- Limited consumption of alcohol and caffeine
- Stress management
- Mental health therapy, if needed
Treatment for fatigue generally depends on its cause, and can usually be accomplished by making the same lifestyle changes that help prevent the condition. For instance, a sleep-deprived individual may eliminate fatigue by going to bed at an earlier time.
Sleep deprivation is, in fact, the first – and perhaps easiest – factor to eliminate when seeking the source of fatigue. Small children generally require 14 hours to 16 hours of sleep, whereas most adults can function regularly with only six hours to eight hours of sleep a night. An adult who averages less than six hours of sleep each night may therefore be contributing to the onset of fatigue. People with sleep disorders may benefit from evaluation and treatment in a sleep clinic.
Individuals with fatigue caused by medical factors, such as disease or infection, may require medications or in some cases surgery to treat the condition and its associated fatigue. Medication-induced fatigue can be eased if the physician is able to prescribe an alternate treatment.
Questions for your doctor about fatigue
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about fatigue:
- Does having fatigue indicate that I have diabetes or a diabetic complication?
- What symptoms in addition to fatigue could suggest I have diabetes?
- What other conditions could my fatigue be indicating?
- Could any of my medications or other treatments be causing or contributing to my fatigue?
- At what point would I need medical treatment for tiredness?
- What diagnostic tests might I need to undergo for fatigue?
- What do my test results show?
- What are my treatment options for fatigue?
- How much exercise should I get, and at what time of the day? Do I need to lose weight or improve my diet?
- Does having diabetes change the amount of sleep I need?
- Am I getting the proper amount of sleep? How can my sleep problems be resolved?