Table of ContentsView AllTable of ContentsSymptomsCausesTreatmentDiagnosisWhen to Seek Medical Care
Table of ContentsView All
View All
Table of Contents
Symptoms
Causes
Treatment
Diagnosis
When to Seek Medical Care
Lethargydescribes a state in which you are exhausted and have little to no energy. It is more profound and long-lasting than simply being tired or sleepy. Lethargy can be a symptom of certain diseases and health conditions or it can be a normal response to not getting enough sleep, stress, or eating poorly.Certain drugs or medications can also cause lethargy.
When lethargy develops as a response to life circumstances, it often resolves with rest,increased sleep, good nutrition, and being active. However, in the case of illness, lethargy can linger for days, weeks, or even months.
Verywell / JR Bee
What is the difference between fatigue and lethargy?While fatigue and lethargy are often used interchangeably, the two states aren’t exactly the same. Fatigue is a persistent and constant feeling of extreme tiredness, sleepiness, or exhaustion. Lethargy is more focused on the low energy a person has. People who experience fatigue typically feel lethargy, or lack of energy, as part of being fatigued.
What is the difference between fatigue and lethargy?
While fatigue and lethargy are often used interchangeably, the two states aren’t exactly the same. Fatigue is a persistent and constant feeling of extreme tiredness, sleepiness, or exhaustion. Lethargy is more focused on the low energy a person has. People who experience fatigue typically feel lethargy, or lack of energy, as part of being fatigued.
Lethargy has been described as unrelenting exhaustion that includes chronic fatigue, lack of energy, and sluggishness. People who are lethargic may also experience:
People who are lethargic may act as if they are in a daze. They may not move as quickly as they usually do and may be aware that they are in poor health.
Other symptoms that may accompany lethargy include:
Lethargy in Babies
The following symptoms are also reasons to seek care right away:
Lethargy has a number of possible causes. It can be the body’s response to not getting enough sleep, overexertion, stress, lack of activity, or improper nutrition. It can also be a side effect of medication or the body’s response to alcohol. Consumption of alcohol while taking certain medications can also cause a person to feel lethargic.
Lethargy is a symptom of many acute (abrupt onset) conditions, including:
Lethargy can also be a symptom of mental health disorders, including major depression and postpartum depression.
Other serious medical conditions that cause lethargy include, but are not limited to:
The first step in determining the cause of lethargy is to see a healthcare provider. They will take your medical history, ask about your symptoms, and perform a physical exam. They may also order tests, including:
Your healthcare provider may also recommend seeing a specialist if the cause of lethargy and other symptoms cannot be established.
When to See a Healthcare Provider
Summary
Lethargy involves more than being tired, sleepy, or drowsy. It is a state of being exhausted, with little to no energy, and it tends to linger. In some cases, lethargy may be due to certain life situations and lifestyle habits, but it can also be a symptom of certain diseases and health conditions. Treatment depends on the underlying cause.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Medline Plus.Fatigue.National Cancer Institute.NCI dictionary of cancer terms: lethargy.Mount Sinai.Fatigue.UnityPoint Health.What does fatigue feel like?Seattle Children’s Hospital.Emergency symptoms not to miss.Stadje R, Dornieden K, Baum E, et.al.The differential diagnosis of tiredness: a systematic review.BMC Fam Pract. 2016 Oct 20;17(1):147. doi:10.1186/s12875-016-0545-5Medline Plus.Dehydration.American Thyroid Association.Hypothyroidism.Medline Plus.Autoimmune diseases.National Institute of Mental Health.Depression.Spathis A, Fife K, Blackhall F, et al.Modafinil for the treatment of fatigue in lung cancer: Results of a placebo-controlled, double-blind, randomized trial.Journal of Clinical Oncology2014 32:18, 1882-1888. doi:10.1200/JCO.2013.54.4346Johns Hopkins Medicine.When to call for help.Additional ReadingAmerican Addiction Centers.The Effects of Mixing Drugs & Alcohol.American Cancer Society.Managing Cancer-related Fatigue.Medline Plus.Dehydration.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Medline Plus.Fatigue.National Cancer Institute.NCI dictionary of cancer terms: lethargy.Mount Sinai.Fatigue.UnityPoint Health.What does fatigue feel like?Seattle Children’s Hospital.Emergency symptoms not to miss.Stadje R, Dornieden K, Baum E, et.al.The differential diagnosis of tiredness: a systematic review.BMC Fam Pract. 2016 Oct 20;17(1):147. doi:10.1186/s12875-016-0545-5Medline Plus.Dehydration.American Thyroid Association.Hypothyroidism.Medline Plus.Autoimmune diseases.National Institute of Mental Health.Depression.Spathis A, Fife K, Blackhall F, et al.Modafinil for the treatment of fatigue in lung cancer: Results of a placebo-controlled, double-blind, randomized trial.Journal of Clinical Oncology2014 32:18, 1882-1888. doi:10.1200/JCO.2013.54.4346Johns Hopkins Medicine.When to call for help.Additional ReadingAmerican Addiction Centers.The Effects of Mixing Drugs & Alcohol.American Cancer Society.Managing Cancer-related Fatigue.Medline Plus.Dehydration.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Medline Plus.Fatigue.National Cancer Institute.NCI dictionary of cancer terms: lethargy.Mount Sinai.Fatigue.UnityPoint Health.What does fatigue feel like?Seattle Children’s Hospital.Emergency symptoms not to miss.Stadje R, Dornieden K, Baum E, et.al.The differential diagnosis of tiredness: a systematic review.BMC Fam Pract. 2016 Oct 20;17(1):147. doi:10.1186/s12875-016-0545-5Medline Plus.Dehydration.American Thyroid Association.Hypothyroidism.Medline Plus.Autoimmune diseases.National Institute of Mental Health.Depression.Spathis A, Fife K, Blackhall F, et al.Modafinil for the treatment of fatigue in lung cancer: Results of a placebo-controlled, double-blind, randomized trial.Journal of Clinical Oncology2014 32:18, 1882-1888. doi:10.1200/JCO.2013.54.4346Johns Hopkins Medicine.When to call for help.
Medline Plus.Fatigue.
National Cancer Institute.NCI dictionary of cancer terms: lethargy.
Mount Sinai.Fatigue.
UnityPoint Health.What does fatigue feel like?
Seattle Children’s Hospital.Emergency symptoms not to miss.
Stadje R, Dornieden K, Baum E, et.al.The differential diagnosis of tiredness: a systematic review.BMC Fam Pract. 2016 Oct 20;17(1):147. doi:10.1186/s12875-016-0545-5
Medline Plus.Dehydration.
American Thyroid Association.Hypothyroidism.
Medline Plus.Autoimmune diseases.
National Institute of Mental Health.Depression.
Spathis A, Fife K, Blackhall F, et al.Modafinil for the treatment of fatigue in lung cancer: Results of a placebo-controlled, double-blind, randomized trial.Journal of Clinical Oncology2014 32:18, 1882-1888. doi:10.1200/JCO.2013.54.4346
Johns Hopkins Medicine.When to call for help.
American Addiction Centers.The Effects of Mixing Drugs & Alcohol.American Cancer Society.Managing Cancer-related Fatigue.Medline Plus.Dehydration.
American Addiction Centers.The Effects of Mixing Drugs & Alcohol.
American Cancer Society.Managing Cancer-related Fatigue.
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