Feeling exhausted despite having a “normal” haemoglobin level? Your iron status may deserve a closer look.
Nutritionist Rashi Chowdhary says that symptoms such as persistent fatigue, restless legs, poor sleep and feeling constantly on edge can sometimes be associated with low iron stores. For women experiencing anxiety alongside fatigue, hair fall or restless legs at night, she suggests discussing iron testing with a healthcare professional.
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Haemoglobin and ferritin tell different stories
According to Chowdhary, haemoglobin and ferritin provide different information about iron status.
Haemoglobin reflects the iron-containing protein in red blood cells that carries oxygen, while ferritin is a marker of the body’s stored iron. She compares the two to money: haemoglobin is the cash in your wallet, while ferritin is your bank balance.
That means a person can have haemoglobin within the laboratory’s reference range while still having relatively low iron stores.
Chowdhary describes a pattern she says she frequently sees: a person feels “wired and tired”—physically exhausted by the end of the day but unable to switch off at night—yet routine bloodwork shows normal haemoglobin. In such cases, she argues, looking only at haemoglobin may not provide the complete picture.
Could low iron affect sleep?
Iron plays several roles in the body, including functions related to the brain and the production of neurotransmitters such as dopamine and serotonin.
Chowdhary also connects low iron stores with restless legs and sleep difficulties. However, symptoms such as fatigue, anxiety, hair loss or poor sleep can have many possible causes, so they should not automatically be attributed to iron deficiency.
Why ferritin shouldn’t be viewed in isolation
Chowdhary recommends considering ferritin alongside C-reactive protein (CRP), a marker that can indicate inflammation.
This is relevant because inflammation can affect ferritin levels, meaning the result may need to be interpreted in the context of other blood tests and a person’s symptoms.
She points out that some laboratories may report ferritin levels around 15 as falling within their reference range. At the same time, clinical guidance for people with restless legs syndrome uses higher ferritin thresholds when considering iron treatment in certain circumstances.
Chowdhary says that, in her own practice, more than half of the women she sees have low ferritin despite having normal haemoglobin.
The takeaway
A normal haemoglobin result does not necessarily tell you how much iron your body has stored. If persistent fatigue, restless legs, sleep problems or hair loss are present, discussing ferritin and the broader iron picture with a healthcare professional may provide additional context.
Importantly, ferritin results should be interpreted alongside symptoms, inflammation markers and other relevant tests rather than used on their own to diagnose iron deficiency or determine whether iron supplements are needed.