Medical questions & health advice by board certified doctors

"Why am I so tired all the time?"

ZocdocAnswersWhy am I so tired all the time?


For the past three months I have slept on average for over 13 hours a night. When I wake up I still feel tired and exhausted. I feel weak and have to stop doing physical activities too. I had my blood checked and everything was normal. Why am I still so tired?


I am sorry to hear about your symptoms. It sounds as if they are significantly affecting your life. In order to provide an accurate diagnosis, a physician would need to review your medical records, collect an updated medical history, and perform a thorough physical exam. Therefore, I strongly encourage you to schedule an appointment with a primary care physician. Only after collecting this information will it be possible to provide a diagnosis. There are many potential causes of extreme fatigue. Hypothyroidism can cause fatigue as well as disturbances of many other organs, and your thyroid function should be investigated. Anemia, or a low red blood cell count, can cause a decrease in your body's oxygen carrying capacity, which leads to fatigue. Extreme fatigue can be a symptom of depression. Infections, such as mononucleosis, can cause severe fatigue. Problems with your heart or lungs can reduce your exercise tolerance leading to fatigue. Medication side effects could explain your symptoms. Additionally, certain nutritional deficiencies could cause extreme fatigue. It is not possible to provide a diagnosis with the limited information provided. I strongly encourage you to schedule an appointment with a primary care physician. After performing a detailed, in-person evaluation, the doctor will be able to discuss potential causes and treatment options.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.