Lethargy

{{short description|State of tiredness, weariness, fatigue, or lack of energy}}

{{distinguish|Fatigue}}

{{For|the 1990s band|Lethargy (band)}}

Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overworking, stress, lack of exercise, improper nutrition, drug abuse, boredom, or a symptom of an underlying illness or disorder. It may also be a side effect of medication or caused by an interaction between medications or medication(s) and alcohol. It may also be an altered level of consciousness.{{Citation |last=Tindall |first=Suzie C. |title=Level of Consciousness |date=1990 |url=http://www.ncbi.nlm.nih.gov/books/NBK380/ |work=Clinical Methods: The History, Physical, and Laboratory Examinations |editor-last=Walker |editor-first=H. Kenneth |edition=3rd |place=Boston |publisher=Butterworths |isbn=978-0-409-90077-4 |pmid=21250221 |access-date=2022-03-26 |editor2-last=Hall |editor2-first=W. Dallas |editor3-last=Hurst |editor3-first=J. Willis}}

When part of a normal response, lethargy often resolves with rest, adequate sleep, decreased stress, physical exercise, and good nutrition.Hall J. E., Guyton A. C. (2006): Textbook of medical physiology, 11th edition. Elsevier Saunders, St. Louis, Mo, {{ISBN|0-7216-0240-1}}. Its symptoms, however, can last days or even months,{{Cite web |title=Chronic fatigue syndrome - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/chronic-fatigue-syndrome/symptoms-causes/syc-20360490 |access-date=2022-03-26 |website=Mayo Clinic |language=en}} so it can be a sign of a recent underlying illness or infection if it does not resolve normally.