What are potential causes of feeling tired and having no strength?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Feeling tired with no strength is often caused by underlying muscle or lung conditions, though it can also stem from anemia, thyroid disorders, infections, or chronic fatigue. Identifying and treating the root cause frequently restores energy and physical strength.

Because fatigue and weakness can point to many different conditions—some minor, some serious—it's important to understand what's driving your symptoms before deciding on next steps. A free, AI-powered symptom check takes just a few minutes, is completely anonymous, and can help you identify possible causes and determine whether you should see a doctor. It's a smart, no-cost first step toward feeling like yourself again.

Reviewed for medical accuracy: 07/14/2026

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Explanation

Feeling tired and having no strength can be caused by different health issues. One reason might be problems with muscles that start in adulthood, as discussed in Reference 1. This can make it hard to do everyday activities.

Another reason could be related to how well your lungs work. Reference 2 explains that if your lungs and the muscles that help you breathe are not strong, it can make you feel weak and tired.

Sometimes, fixing a health problem can help. For example, Reference 3 talks about how people felt stronger after a surgery to fix a problem with a gland in their neck. This shows that when certain health issues are treated, people can feel better and have more strength.

If you are feeling tired and weak, it's important to talk to a doctor. You can start by using a free symptom checker to better understand what might be causing your symptoms and how to make it better.

(References)

Riggs JE. (1985). Adult-onset muscle weakness. How to identify the .... Postgraduate medicine, 4034446.
Forti M, Zamunér AR, Andrade CP, & Silva E. (2016). Lung Function, Respiratory Muscle Strength, and .... Respiratory care, 27094397.
Kristoffersson A, Boström A, & Söderberg T. (1992). Muscle strength is improved after parathyroidectomy in .... The British journal of surgery, 1555067.

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