Fatigue

What is it?

Fatigue is more than ordinary tiredness — it is a persistent, often debilitating lack of energy that does not improve with sleep or rest. It can be physical, mental, or both, and is one of the most commonly reported symptoms across medicine. Fatigue is a core feature of many chronic conditions including major depressive disorder, hypothyroidism, anemia, diabetes, and chronic fatigue syndrome (ME/CFS). When fatigue is described as anergia — a profound, pervasive absence of energy — it strongly suggests an underlying medical or psychiatric condition requiring evaluation.

Common causes

When to see a doctor

• 1Fatigue is severe or has lasted more than 2–4 weeks without improvement
• 2You also have unexplained weight loss, fever, or night sweats
• 3You feel sad, hopeless, or have lost interest in activities you once enjoyed
• 4Fatigue is accompanied by chest pain, shortness of breath, or palpitations
• 5Your sleep is non-restorative — you wake up exhausted regardless of hours slept
• 6Fatigue is affecting your ability to work, care for yourself, or maintain relationships

What you can do

• ✓Prioritize consistent sleep: same bed and wake time daily, even on weekends
• ✓Short walks or light physical activity — even 10 minutes can improve energy levels
• ✓Limit caffeine after noon; avoid using it to mask fatigue rather than address it
• ✓Stay hydrated — mild dehydration is a common but overlooked cause of tiredness
• ✓Break large tasks into smaller steps; rest proactively before you are exhausted (pacing)
• ✓Track when fatigue is worst to help identify patterns or triggers

Conditions that cause this symptom

Medications that may help

Treatment depends on the underlying cause. Always consult your provider before starting any medication.

Frequently asked questions