When is it time to get fatigue checked out?

Everyone feels tired sometimes. But when does feeling tired cross the line to being fatigued? Mayo Clinic experts answer common questions about fatigue — and when it's time to see your health care provider.

How is fatigue different from feeling tired?

Fatigue is feeling weak and lacking energy for everyday activities. If you're fatigued, you might need to rest during the day and doze off when you sit down. If rest doesn't lessen your tired feeling, you might be fatigued.

What causes fatigue?

There are many causes of fatigue. Some may include:

  • Lack of physical activity or excessive physical activity.
  • Unhealthy eating habits.
  • Some medicine, including allergy medicine and antidepressants.
  • Medical treatments like chemotherapy, radiation and surgery.
  • Health conditions like heart disease, diabetes and thyroid disease, fibromyalgia, and COVID-19.
  • Anemia, which could indicate a deficiency in iron or vitamins B-12 or B-9.
  • Depression.
  • Sleep disorders like obstructive sleep apnea or the inability to get enough sleep at night.

What should I do if I'm feeling fatigued?

Sometimes fatigue can improve with physical activity or a healthy diet. Try going for a walk, talking to a friend, or enjoying some fresh fruits and veggies.

If you just can't shake your fatigue despite these efforts, start tracking your energy levels. For example:

  • When you first noticed the fatigue.
  • When you feel it during the day.
  • If anything improves your energy levels.
  • How fatigue affects your life.
  • Any other symptoms like change in pain, appetite, weight, mood, or sleep quality and duration.

When should I see my health care provider?

Schedule a checkup with your health care provider if:

  • You lack energy for 2 weeks or longer despite resting, eating well and exercising.
  • Your usual activities leave you breathing heavy or needing a break. For example, you suddenly need to take breaks between carrying in grocery bags. Or you could previously walk several blocks but now get winded after one block.
  1. Fatigue. Mayo Clinic. https://www.mayoclinic.org/symptoms/fatigue/basics/definition/sym-20050894. Accessed Aug. 30, 2022.
  2. Fatigue in older adults. National Institute on Aging. https://www.nia.nih.gov/health/fatigue-older-adults. Accessed Aug. 31, 2022.
  3. DeSimone CV (expert opinion). Mayo Clinic. Oct. 16, 2021.