Constant fatigue and weakness: what to do
Constant fatigue is most often caused by lack of sleep, overwork and stress, but sometimes it's a symptom of anemia, thyroid disease, high blood sugar or depression. If you've had no energy for several weeks even though you get enough sleep, see an internist. Testing usually starts with a complete blood count, ferritin, TSH and glucose.
What causes constant fatigue
Usually the cause is your daily routine. Most adults need 7–9 hours of sleep a night, and people who sleep less or often wake up at night eventually feel tired as soon as they get up. Long workdays without breaks and night shifts also wear you down. Sleep gets worse with anxiety, alcohol in the evening and coffee in the afternoon.
After flu, COVID-19 or another infection, weakness can last several weeks. If you feel a little stronger each week, that’s normal recovery after an illness.
When fatigue is a symptom of illness
If you sleep well but have had no energy for weeks, doctors look for a medical cause. They most often check for:
- anemia and iron deficiency, especially in women with heavy periods and during pregnancy
- an underactive thyroid, when fatigue comes with feeling cold, dry skin and weight gain
- high blood sugar, which brings thirst and frequent urination
- vitamin B12 or vitamin D deficiency
- depression and anxiety disorders
- chronic infections or heart, kidney or liver disease
- side effects of medicines you take
Sleep apnea is another possibility. A person snores, stops breathing for a few seconds during sleep and wakes up exhausted even after eight hours in bed. If your family has noticed such pauses, be sure to tell your doctor.
What you can change yourself
Start with what’s in your control:
- go to bed and get up at the same time, even on weekends
- put your phone away an hour before bed and drink coffee only in the first half of the day
- move every day, even if it’s just a 30-minute walk
- eat regular meals with vegetables, grains, meat, fish or beans
- cut down on alcohol, since it disrupts sleep
For a week, write down when you go to bed and wake up and how you feel in the morning. This diary helps you and your doctor see whether your routine is the problem.
Don’t take vitamins or iron “for energy” without tests. Too much iron is harmful, and pills can hide the cause that needs to be found. Medicines are prescribed by a doctor once they’ve seen your test results.
If several weeks of a normal routine haven’t given you more energy, it’s time to see a doctor.
Which blood tests to take for fatigue
At the appointment, describe your tiredness as precisely as you can: when it started, whether you have energy in the morning, whether it eases after the weekend, and whether your weight, appetite or mood have changed. The internist decides which tests you need after talking to you and examining you, since that depends on your symptoms. The usual starting point is:
- a complete blood count to check hemoglobin and rule out anemia
- ferritin, which shows your iron stores
- TSH, the hormone used to check how your thyroid works
- fasting blood glucose or glycated hemoglobin (HbA1c)
- if needed, a blood chemistry panel, a urinalysis, vitamin B12 or vitamin D
If you have a declaration with a Viva Clinic family doctor, a complete blood count, urinalysis and glucose test are free with their referral. Ferritin, TSH, vitamin B12 and D, and blood chemistry tests are available for a fee at Diagnost-Lab at 32 Sobornosti St, 4th floor. Blood is taken in the morning after 12 hours without food; water is fine. When your results are ready, you get a Viber message.
Why you shouldn’t try to raise low ferritin on your own is explained in the article on the ferritin test.
Bring your results back to an internist consultation at Viva Clinic. The doctor will explain what they mean and refer you to an endocrinologist or another specialist if needed. The internist sees patients at 27a Sobornosti St or 3 Danyla Halytskoho St (the address is confirmed when you book), and you can book by phone or on Viber.
When to see a doctor urgently
Call an ambulance on 103 if weakness comes on suddenly together with chest pain, difficulty breathing, numbness in an arm or leg, slurred speech or fainting.
See a doctor the same day if:
- you notice black stools or blood in your stool
- you have a high fever that won’t go away
- you’re very thirsty and urinating often
- your skin or the whites of your eyes turn yellow
- you have thoughts of harming yourself; if you fear for your safety right now, call 103
Book an internist appointment within the next few days if you’re losing weight for no reason, sweating heavily at night, or notice swollen lymph nodes or shortness of breath during everyday activity.
Questions and answers
Which doctor should I see if I'm always tired?
Start with an internist or a family doctor. They'll ask questions, examine you, order basic tests and, based on the results, decide whether you need an endocrinologist, a cardiologist or another specialist. At Viva Clinic, these doctors see patients in Slavuta.
Can you be iron deficient with normal hemoglobin?
Yes. Iron stores run low before hemoglobin drops, and fatigue can already appear at this stage. That's why doctors often add a ferritin test to the complete blood count, since ferritin shows how much iron your body has in reserve.
Can fatigue be a sign of depression?
Yes. With depression, tiredness lasts most of the day along with low mood, loss of interest in usual activities and poor sleep. If this lasts more than two weeks, tell your family doctor: screening and first-line help for anxiety and depression are among the free services under a declaration.
