What are the causes of tiredness?

Common Causes of Tiredness

Tiredness is most commonly caused by sleep disturbances, emotional distress, anemia, medication side effects, and underlying medical conditions that should be systematically evaluated to determine appropriate treatment. 1

Primary Assessment of Fatigue

When evaluating tiredness, quantifying severity is essential:

• Mild fatigue (1-3/10): Requires basic education only
• Moderate fatigue (4-6/10): Requires thorough evaluation
• Severe fatigue (7-10/10): Requires prompt and comprehensive assessment 1

Common Treatable Causes

1. Sleep Disturbances

• Sleep disorders affect 30-75% of patients with fatigue 2
• Poor sleep hygiene behaviors include irregular sleep schedules and poor sleep environments 2
• Sleep apnea should be evaluated, especially after treatments affecting upper airways or body composition 2
• Cognitive behavioral therapy is considered the treatment of choice for insomnia 2

2. Emotional Distress

• Depression and anxiety frequently co-occur with fatigue 2
• Depression should be screened for with questions about feeling dejected, sad, or experiencing less pleasure 1
• Fatigue and depression have been documented as concurrent symptoms, with fatigue being an independent predictor of depression 2

3. Anemia

• Common cause of fatigue that should be evaluated with complete blood count 1
• Can result from deficiencies, malabsorption, impaired dietary intake, chronic bleeding, or inflammation 2
• Iron supplementation can be effective for iron deficiency anemia, with intravenous iron being more effective for replenishing iron stores 3

4. Medication Side Effects

• Many medications list fatigue as a common adverse effect
• Levothyroxine overdosage can cause fatigue, increased appetite, and heat intolerance 4
• Review all prescription, over-the-counter medications, and supplements 2

5. Endocrine Disorders

• Thyroid dysfunction is one of the first explanations to consider 5
• Adrenal insufficiency can cause significant fatigue 2
• Diabetes and metabolic disorders can contribute to fatigue 5

6. Nutritional Deficiencies

• Vitamin deficiencies (B6, B12, folate, vitamin D) can cause fatigue 2
• Mineral deficiencies (ferritin, copper, zinc, magnesium) should be evaluated 2
• Nutrient status should be restored if necessary 2

7. Activity Level

• Both excessive exercise and sedentary lifestyle can contribute to fatigue 1
• Structured exercise programs with gradual progression can help manage fatigue 1
• Warning signs of excessive training include persistent fatigue and inability to complete planned workouts 1

8. Substance Use

• Alcohol and drug abuse are associated with emotional distress, poor sleep quality, and fatigue 2
• Always assess for substance use when evaluating fatigue 2

9. Inflammation and Chronic Disease

• Chronic inflammation can cause persistent fatigue 2
• Active disease in conditions like inflammatory bowel disease increases fatigue rates 2
• Cancer-related fatigue affects 70-90% of patients 6

Evaluation Approach

Laboratory Studies

• Initial testing should include:
  • Complete blood count
  • Comprehensive metabolic panel
  • Thyroid-stimulating hormone
  • Inflammatory markers (ESR, CRP) if indicated
  • Iron studies, vitamin B12, folate, and vitamin D levels 1

Management Strategies

1. Treat Underlying Conditions:

   • Correct anemia, hypothyroidism, or other identified medical causes 1
   • Address sleep disorders with appropriate interventions 2

2. Non-pharmacologic Approaches:

   • Structured exercise program with both aerobic and resistance components 1
   • Energy conservation strategies (scheduling activities during peak energy times) 1
   • Sleep hygiene optimization 1
   • Cognitive behavioral therapy for persistent fatigue 1

3. Pharmacologic Interventions (when appropriate):

   • Selective serotonin reuptake inhibitors for depression-related fatigue 7
   • Short-term hypnotics for insomnia 2
   • Caffeine or modafinil for episodic situations requiring alertness 7

Common Pitfalls to Avoid

• Ignoring psychological factors like depression and anxiety 1
• Relying solely on medications rather than incorporating lifestyle modifications 1
• Missing medication side effects as a common cause of fatigue 1
• Failing to quantify fatigue severity, which can lead to inadequate evaluation 1
• Recommending increased exercise for all patients with fatigue, which can worsen symptoms in certain conditions 1

Remember that fatigue is often multifactorial, and a systematic approach to identifying and addressing all contributing factors is essential for effective management.