Loss of energy and weakness in the body: possible causes

You wake up feeling drained and by midday you're already out of energy. Resting on the weekend changes nothing. This condition is called loss of energy, and it often has a specific cause.

Weakness and loss of energy: what lies behind it

Fatigue is a normal reaction to exertion, stress, or lack of sleep. Weakness that persists for weeks without a clear cause is already a symptom.

Doctors describe asthenia as a condition with increased fatigability. It is hard to endure mental and physical strain for long. Loud sounds, bright light, and strong smells are irritating. Mood fluctuates, and sleep does not restore energy.

Asthenia can be psychogenic, from mental overstrain. And somatogenic, when it is caused by a disease. Senile asthenia is distinguished separately: usually after age 60–65, in about 10% of people of that age.

Common causes of weakness in the body

• lack of sleep and insomnia;
• stress, depression, severe life events;
• hormonal changes: adolescence, pregnancy, menopause;
• infections such as glandular fever and COVID-19;
• certain medications and treatments, for example chemotherapy.

The list is broader. Chronic diseases of the heart, lungs, liver, kidneys, and thyroid cause constant fatigue. The same happens with untreated pain, fibromyalgia, infections, Parkinson's disease, and after a stroke. Weakness goes hand in hand with depression and anxiety.

After a coronavirus infection, asthenia persists for two months in 60% of patients. It also appears with vitamin B12 deficiency.

When weakness is a reason for concern

If the cause is unclear and the condition does not resolve, this is a reason to see a doctor.

Weakness by itself is not a reason to call an ambulance. Call 103 or 112 if it is accompanied by signs of a stroke or heart attack that are life-threatening.

Anemia, thyroid, sugar: which conditions cause weakness

Some conditions that cause fatigue are checked with blood tests.

Iron-deficiency anemia: no energy, noticeable palpitations, shortness of breath, pale skin.

Diabetes mellitus: severe fatigue, constant thirst, frequent urination, especially at night, weight loss.

Hyperthyroidism: fatigue around the clock, difficulty sitting still, nervousness, anxiety, muscle weakness.

Myalgic encephalomyelitis, also known as chronic fatigue syndrome, is distinguished separately. Extreme fatigability persists for at least 3 months and interferes with everyday tasks. Memory and concentration lapses are added, and symptoms resemble the flu.

Which tests help find the cause

First the doctor talks with you. They ask about sleep, appetite, daily activities, and physical exertion. Then they perform an examination.

Next are blood tests. They show anemia, diabetes, and increased thyroid function.

If the cause is unclear, the doctor refers you to a relevant specialist.

When to see a doctor

See a doctor if fatigue persists for several weeks and you do not understand why. Or if it interferes with living and working.

A reason for a visit is fatigue together with other symptoms: weight loss or mood changes. And complaints from loved ones about loud snoring, gasping, and sounds of suffocation during sleep. It resembles sleep apnea.

This material is for reference: it helps you get your bearings, but does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer