Question 68 of 433
My blood work is “normal.” Why am I so tired?
The short answer
A normal blood count does not rule out every cause of fatigue. Ferritin can be useful when iron deficiency is plausible, but the evaluation begins with the history.
You can have a normal blood count and still be low in iron. I explain it this way: hemoglobin is cash, and ferritin is savings. You can be spending normally with the savings account empty. Low ferritin causes fatigue, hair shedding, restless legs, and poor exercise tolerance, especially in women who menstruate, people who donate blood, endurance athletes, and anyone on acid-blocking drugs. If it is low, the next step is to find out why, since in adults over 50 the cause can be bleeding from the gut.
Depending on the history, B12, TSH, or a sleep evaluation may help. Vitamin D testing needs a clinical indication. Mood, bleeding, nutrition, alcohol, and medications also deserve attention.
“This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship.” From the book’s medical disclaimer. Full disclaimer
CLINICAL / HUMAN STUDIES — Symptomatic patients: iron deficiency can occur without anemia; testing and benefit depend on context.Evidence grade (draft mapping)Grade pendingPart 5, Q68 · Sources: R2
Sources cited
- R2 Demay MB et al. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. 2024;109:1907–1947. doi:10.1210/clinem/dgae290. PubMed 38828931DOI 10.1210/clinem/dgae290✓ Verified
From Longevity Unmasked by Afshine Ash Emrani, MD, FACC. Medical disclaimer. This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship. Nothing here is meant to diagnose, treat, cure, or prevent any disease. Medicine is personal: a test, drug, supplement, or exercise plan that helps one person can harm another. Do not start, stop, or change any medication or treatment because of something you read in these pages. Talk with a licensed clinician who knows your history first. If you think you are having a medical emergency, call 911. The author disclaims responsibility for any loss or harm arising from use of the information in this book.