Written & medically reviewed by Dr. Sanjay Anbu, MBBS· Last reviewed
Constant tiredness is one of the most common health complaints. Often it is lifestyle — poor sleep, stress or diet — but sometimes it signals a treatable medical cause like anaemia or thyroid problems. Here is how to think about it.
Iron-deficiency anaemia (very common, especially in women)
Thyroid problems (an underactive thyroid)
Uncontrolled diabetes or blood-sugar swings
Vitamin B12 or vitamin D deficiency
Dehydration, poor diet or too little activity
When to see a doctor urgently
Tiredness with breathlessness, chest pain or a racing heart
Unexplained weight loss, fever or night sweats
Extreme, sudden or worsening exhaustion
Feeling faint, very pale, or noticing blood loss
Simple tests can find the cause. Blood tests (like CBC, thyroid, sugar and vitamins) often reveal a treatable reason for fatigue. MedDroid gives general information, not a diagnosis.
Frequently asked questions
When should I worry about being tired all the time?
See a doctor if tiredness lasts more than a few weeks, is severe, or comes with warning signs like weight loss, breathlessness, fever or heavy periods.
What blood tests check for fatigue?
Common ones are a full blood count (for anaemia), thyroid tests, blood sugar/HbA1c, and vitamin B12 and D levels. Your doctor chooses based on your history.
Can vitamin deficiency cause tiredness?
Yes. Low iron, vitamin B12 or vitamin D are common, treatable causes of ongoing tiredness, so they are often checked.
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.