Lethargy is often described by lack of energy, tiredness, and fatigue. Lethargy is a normal response to lack of sleep, exercise, stress, and/or overexertion. In most cases, lethargy can be managed with rest, decreased stress, exercise, and good nutrition.

Lethargy, or extreme fatigue, can be caused by:
  • Allergies
  • Asthma
  • Anemia
  • Cancer and cancer treatments
  • Chronic pain
  • Infection
  • Depression
  • Thyroid problems


Lethargy itself is rarely considered an emergency, however, if it develops suddenly or has concerning symptoms, visit Our Urgent Care immediately.

What is fatigue and how does it occur?

Fatigue is a condition of weakness that can be both physical and mental.

Fatigue may be caused by:
  • Illnesses
  • Thyroid problems
  • Overexertion
  • Lack of sleep
  • Poor diet
  • Stress
  • Certain medications
What are the symptoms of fatigue?
  • Lack of energy
  • Weakness
  • Tiredness