Fatigue affects almost everyone at some point in time. It can be a normal response to overexertion, stress or minor illness (such as a cold). However, it can also be a symptom of a medical condition or serve as a signal that a disease has progressed or worsened.

Fatigue can show up in a number of different ways, including:

• Weariness
• Daytime sleepiness
• Lack of energy
• Generally feeling tired

Most people can recover from fatigue due to non-medical origins in a relatively short period of time. However, continually getting inadequate amounts and quality of sleep can create a sleep debt even in otherwise healthy people. Long-term sleep debt can cause health problems that require medical attention. Fatigue alone can also significantly influence the ability of people to function.

Among the many factors that may cause fatigue are allergies and asthma. The overactive immune system response associated with allergies and asthma can be taxing on the body and cause fatigue. Therefore, fatigue is one symptom that may lead to a diagnosis of these conditions.

For people with asthma, fatigue can also be an important warning sign that existing treatments are not effectively controlling asthma symptoms. Asthmatics should take episodes of fatigue seriously and consult their physician. Fatigue may be a sign of impending asthma attack or respiratory failure.

Fatigue may also be a side effect of asthma or allergy medication (e.g., anticholinergics, oral steroids, leukotriene modifiers, antihistamines).

Fatigue that is related to a lack of sleep can only be addressed by getting sleep. For people with medical conditions, sudden incidents of fatigue should be followed by a trip to the physician and/or hospital. A combination of illness and disturbed sleep may be a significant barrier to patient recovery.

Physicians may perform a variety of diagnostic tests to determine the origin of the fatigue. Recommended treatment methods will focus on achieving adequate rest and address any underlying medical conditions causing fatigue.