Feeling tired after a long day is normal. Feeling tired every day, no matter how much you sleep, is not. Persistent fatigue is one of the most common reasons patients visit a general physician, and the good news is that the vast majority of causes are identifiable and treatable. The challenge is that fatigue has dozens of possible causes, from simple lifestyle factors to underlying medical conditions, which is why it often takes a proper evaluation to find the answer.
What is fatigue and how is it different from ordinary tiredness?
Ordinary tiredness resolves after rest or a good night of sleep. Fatigue does not. Fatigue is a persistent, overwhelming sense of low energy that interferes with daily activities, concentration, mood, and motivation. It may be physical, mental, or both. If you have been sleeping 7 to 8 hours but still feel exhausted when you wake up, that is the key signal that something beyond poor sleep is at play.
What are the most common medical causes of constant tiredness?
- Iron deficiency anaemia: low haemoglobin means your blood carries less oxygen to your muscles and brain. Fatigue, paleness, shortness of breath, and cold hands are typical signs.
- Hypothyroidism: an underactive thyroid slows your metabolism. Fatigue, weight gain, hair thinning, and feeling cold all the time are common.
- Vitamin B12 or vitamin D deficiency: both are extremely common in India and both cause profound fatigue along with other symptoms.
- Diabetes (uncontrolled): high blood sugar prevents your cells from using glucose effectively, leaving you drained despite eating.
- Sleep apnoea: you may not know you stop breathing repeatedly during sleep. Partners often notice the snoring. The result is unrefreshing sleep no matter how long you stay in bed.
- Depression and anxiety: mental health conditions are among the leading causes of fatigue worldwide and are frequently underdiagnosed.
- Chronic infections or inflammation: conditions such as tuberculosis, viral hepatitis, or autoimmune disease can cause persistent low energy.
- Heart or kidney disease: both reduce the body's efficiency and present with fatigue as an early symptom.
What lifestyle factors cause fatigue?
- Poor sleep quality or irregular sleep patterns
- A diet low in iron, B12, or protein
- Dehydration, which is easy to underestimate in Pune's summer heat
- Sedentary lifestyle, where low activity paradoxically reduces energy levels
- Excess caffeine that disrupts sleep architecture
- Chronic stress without adequate recovery time
When should I see a doctor for tiredness?
See a doctor if your fatigue has lasted more than two to four weeks, disrupts your work or daily life, is accompanied by unexplained weight loss, fever, night sweats, breathlessness, chest pain, swollen glands, or very pale skin, or if you feel too exhausted to get out of bed most mornings despite sleeping adequately. These features suggest an underlying medical cause that needs investigation rather than lifestyle adjustment alone.
What tests does a doctor typically run for fatigue?
A general physician will take a detailed history and usually start with a full blood count (to check for anaemia), thyroid function tests, fasting blood sugar, and vitamin B12 and D levels. Depending on the findings, liver and kidney function tests, iron studies, or further specialist referral may follow. Many causes of fatigue are diagnosed on a simple panel of routine blood tests.
A word from our clinic
I am Dr. Rajiv Kumar, general physician at Prudent International Health Clinic in Viman Nagar, Pune. Fatigue is never something to simply push through indefinitely. In my experience, a straightforward blood panel identifies the cause in the majority of patients who come in feeling constantly tired. Please do not wait months hoping it passes on its own. We are here all 7 days, 9 AM to 9 PM. Call or WhatsApp us on +91 70287 22200 to book an appointment. For current consultation charges, call the clinic.
