Fatigue is easy to blame on lack of sleep and on the idea that 'you need to run more.' But then you learn how doctors explain fatigue and see it differently: sometimes it really is a lack of sleep, and sometimes it is a signal that you need to see a doctor.
When fatigue is already a symptom
Feeling tired sometimes is normal. Causes can be everyday ones — lack of sleep, an unhealthy lifestyle, stress, depression, hormonal changes during puberty, pregnancy, or menopause, some illnesses and treatments. Common causes also include illnesses such as glandular fever and COVID-19 and some treatments like chemotherapy. But if you cannot explain the fatigue, it lasts a long time and does not go away — it may be a sign of a medical condition. And the main thing here is not to self-diagnose.
Thyroid gland and hypothyroidism
Hypothyroidism is when the gland in the neck produces too few hormones. Common symptoms include extreme fatigue, feeling cold more often than others, weight gain, constipation, difficulty concentrating, low mood, dry skin and hair, a hoarse voice, irregular or heavy periods. Symptoms usually develop slowly and worsen over time. The doctor asks about symptoms, family history of thyroid disease or autoimmune conditions, and recent pregnancy. Hypothyroidism is more often diagnosed in women aged 30–60, and in most cases it is primary (that is, caused by damage to the gland itself).
The opposite can also happen: hyperthyroidism also causes fatigue. A person is tired all the time, finds it hard to sit still, and has nervousness, anxiety, irritability, and muscle weakness.
How it is checked: the doctor may examine the neck, and then — a blood test for thyroid-stimulating hormone (TSH) and thyroxine (T4). Sometimes they refer you to a specialist.
Causes of hypothyroidism include the autoimmune disease Hashimoto's: the immune system attacks the gland, and it cannot produce enough hormone. The disease is more common in women and usually begins at age 30–50, although hypothyroidism can occur in anyone. Other causes include other thyroid diseases such as thyroiditis, surgery or radiation to the neck area, treatment for hyperthyroidism, iodine deficiency in the diet, and taking certain medications. The risk is higher if there has already been thyroid disease in the family.
If hypothyroidism is not treated or the wrong dose of medication is taken, the risk of heart problems increases, including coronary heart disease and heart failure, and bone problems, including osteoporosis. In very rare cases, severe hypothyroidism leads to myxedema coma — a life-threatening condition that requires hospital treatment; it is more common in older people.
Blood sugar: fluctuations and diabetes
Fatigue can be caused by diabetes. Its clues are severe fatigue, intense thirst, frequent urination (especially at night), and weight loss. That is, if fatigue comes together with these symptoms, it is a reason not to delay a visit. The doctor may order blood tests to check for diabetes as well.
Adrenal glands, stress, and deficiencies
Common causes of fatigue include stress; whether additional tests are needed is decided by the doctor.
Iron-deficiency anemia is among the conditions that cause fatigue. Its clues are lack of energy, noticeable palpitations, shortness of breath, and pale skin. Iron-deficiency anemia is confirmed by a blood test.
Chronic fatigue syndrome and sleep apnea
Chronic fatigue syndrome (ME/CFS) is considered separately. Its signs: pronounced fatigue for at least 3 months that greatly interferes with daily activities, problems with thinking, memory, and concentration, flu-like symptoms. Another cause is sleep apnea: daytime fatigue due to nighttime awakenings and loud snoring.
Which doctor to see and with which complaints
- unexplained fatigue lasting for weeks
- fatigue interferes with daily activities
- fatigue plus weight loss or mood changes
- loved ones have heard you gasping, snoring, or sniffling at night
With these complaints, people go to a family doctor. They may refer you for blood tests — for anemia, diabetes, or hyperthyroidism — or to a specialist if the cause is unclear. Treatment depends on the cause: it may include talking therapies such as cognitive behavioral therapy, advice on sleep, relaxation, or lifestyle changes.
Call an ambulance immediately (103 or 112) if there are signs of a stroke or heart attack.
My realistic conclusion: fatigue is a bad reason for self-diagnosis, but a good reason to talk to a doctor. This material is for reference and does not replace a doctor's consultation.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer