Top 9 Causes of Fatigue

Find out what typically causes fatigue and how your doctor figures out why you’re so tired.

Sanaz Majd, MD,
October 24, 2013
Episode #077

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The History


  1. Medications
    Some medications, like those prescribed for blood pressure, can cause fatigue as a side effect.  Frank hasn’t seen a doctor in over 10 years, let alone taken any medications.  He also denies taking any over-the-counter supplements or herbal remedies. 

  2. Alcohol/Drugs
    Excessive alcohol intake and illicit drug abuse often runs through my mind as a possible cause of fatigue, but Frank tells me he drinks one glass of red wine with dinner maybe once a week and that he’s never dabbled in any drugs.

  3. Depression
    One of the most common ways patients with depression present at the doctor’s office is with complaints of fatigue.  Often, patients are so depressed that they don’t want to go out or do the things they used to enjoy; doctors call this “anhedonia.” When I ask my patients with fatigue if they are depressed, they sometimes break down crying (this is why I always make sure to stock a box of tissues in each one of my exam rooms).  Frank tells me that although he’s had more stress at work, he’s never been happier.

  4. Excessive Caffeine
    Those who drink excessive caffeine often get a burst of energy initially, but then may crash after the effects wear off.  Frank says he drinks 1 cup of coffee in the mornings, and stays away from sodas and energy drinks.

  5. Thyroid Disease
    Hypothyroidism, where the thyroid is underactive and produces too little hormone, can slow down the metabolism and cause fatigue.  It is often hereditary, but Frank says that no one in his family suffers from this ailment.

  6. Anemia
    I always ask about heavy periods in women, and any bleeding in the stool or elsewhere in both men and women with fatigue.  This is because anemia is also on my list of possibilities anytime a patient complains of fatigue.  If our red blood cells don’t have enough iron, they can’t carry oxygen properly, causing us to feel tired.  Frank denies seeing any blood in his stools.