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Persistent tiredness or exhaustion that doesn't improve with rest. Can significantly impact work, relationships, and quality of life.
There are several possible causes. Here are the most common ones:
Not getting enough quality sleep, regardless of hours in bed.
You might suspect this if you have:
Anxiety, depression, and chronic stress are major causes of fatigue.
You might suspect this if you have:
Diet, exercise, caffeine, and alcohol can all affect energy levels.
You might suspect this if you have:
Low red blood cells or haemoglobin affecting oxygen delivery.
You might suspect this if you have:
Underactive thyroid (hypothyroidism) commonly causes fatigue.
You might suspect this if you have:
High blood sugar can cause persistent tiredness.
You might suspect this if you have:
Important: This information is for general guidance only and should not be used to self-diagnose. A doctor can properly assess your symptoms and provide appropriate advice.
Call 000 or go to Emergency immediately
Fatigue is one of the most challenging symptoms in medicine because it has so many possible causes. When someone tells me they are always tired, my approach is systematic: first, I assess lifestyle factors — sleep quality, work hours, stress, diet, exercise, alcohol, caffeine. These account for the majority of fatigue. Second, I consider medical causes that need screening: iron deficiency (very common in menstruating women), thyroid dysfunction, diabetes, vitamin D deficiency, sleep apnoea, depression, and chronic infections. Third, I ask about the pattern — is the fatigue constant or episodic? Does rest help? Is it physical exhaustion or mental fog? These distinctions guide investigation. Blood tests are often warranted to rule out treatable causes. The reassurance I give patients is that most causes of fatigue are identifiable and treatable.
Medical certificate guidance: Fatigue severe enough to impair concentration, reaction time, or physical function is a legitimate reason for time off. If your work involves driving, operating machinery, or making safety-critical decisions, working while severely fatigued is genuinely dangerous.
All clinical decisions are made by AHPRA-registered doctors following our clinical governance framework. We never automate clinical decisions.
Yes, if your fatigue is significantly affecting your ability to work safely or effectively. This might be while underlying causes are being investigated.
Common tests include full blood count (for anaemia), thyroid function, blood sugar, and sometimes vitamin levels (B12, vitamin D). Your doctor will advise based on your symptoms.
No, fatigue is very common and often related to lifestyle factors, stress, or minor illnesses. However, persistent unexplained fatigue should be investigated.
It depends on the cause. Lifestyle-related fatigue may improve within weeks of making changes. Medical causes may take longer depending on treatment.
If your symptoms are keeping you from work or study, you can request a medical certificate through InstantMed. A doctor will review your symptoms and issue a certificate if clinically appropriate — typically for 1 to 3 days depending on severity. You don't need to be dramatically unwell; feeling genuinely too rough to function is reason enough.
Yes. Australian-registered doctors can assess your symptoms and issue valid medical certificates via telehealth. You fill in a detailed health questionnaire, a doctor reviews it, and if appropriate, your certificate is delivered digitally. No waiting room required.
You complete a structured health questionnaire covering your symptoms, duration, severity, and relevant medical history. The reviewing doctor uses this information — the same clinical reasoning they'd apply in a face-to-face consult — to determine whether a certificate, advice, or referral is appropriate.
A medical certificate covers the period stated on the document. If your symptoms worsen or don't improve as expected, you should see a GP in person or visit your nearest emergency department if it's urgent. Your certificate doesn't replace ongoing care — it's a point-in-time clinical assessment.
In some cases, yes. If a doctor reviewing your request determines that a common, non-restricted treatment is appropriate, they may issue a prescription as part of a consultation. Not all symptoms require or qualify for a prescription — the doctor will advise you on next steps.
Medical certificates are typically issued in under 30 minutes, available 24/7. Other requests are reviewed within 1–2 hours during operating hours (8am–10pm AEST, 7 days). You'll receive an email notification once your request has been reviewed.
If your symptoms suggest something that requires a physical examination, diagnostic tests, or specialist referral, the doctor will let you know and recommend appropriate next steps. Your safety is the priority — telehealth is a great option for many things, but it's not a replacement for hands-on assessment when that's what's needed.
No Medicare card is required for medical certificates. If you're requesting a prescription or consultation, a valid Medicare card is needed. Our service is private and does not attract a Medicare rebate, though any prescriptions issued can still attract PBS subsidies at the pharmacy.
Our Australian-registered doctors can assess your symptoms and provide advice, treatment, or medical certificates if needed.
Get assessed by a doctorThis information is for general educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making decisions about your health. Content on this page has been reviewed by AHPRA-registered Australian doctors but does not replace a personalised medical consultation.