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Why Does Anemia Cause Insomnia? (Iron Deficiency Side Effects)

by Dale Cudmore | Updated: Jan 04, 2023

Research shows a significant link between anemia and insomnia (among other conditions).

I’ve spent a few hours reading over all the relevant research on this topic, and I’ll summarize it for you in an easy to understand way in this post.

As always, especially with a condition like anemia, your treatment path should be dictated by a doctor.

Side Effects of Anemia: Insomnia, Anxiety, Depression

When you look at people with iron deficiency anemia, they are much more likely to have 3 other major conditions (1):

  • Insomnia
  • Anxiety
  • Depression

Without getting into too much detail, people with anemia in one study had an average Pittsburgh Sleep Quality Index score of 6.71, while the non-anemic control group had an average score of 4.11.

Any score under 5 is considered a “good” sleeper. You can use this quick Pittsburgh Sleep Quality Index Online Calculator if you’re curious about your own score.

Other research has shown that people with non-iron deficient anemia are also more likely to experience insomnia symptoms (2).

Why Does Anemia Cause Insomnia?

Research has uncovered a few different ways that anemia can cause sleep troubles.

However, it’s likely that more mechanisms will be discovered over time (or in more detail).

1. Iron Deficiency Impairs Neurotransmitters Needed for Sleep

Sleep is controlled in the brain through very complex interactions between neurotransmitters.

Iron deficiency causes impaired function of some of these neurotransmitters, including: serotonin, noradrenaline, and dopamine (3).

SummaryWithout getting into biochemistry, the gist of the story is that without proper levels of those neurotransmitters at certain times, sleep suffers.

2. Anemia Changes the Structure of Sleep

The sleep cycle has evolved over millions of years. There’s a reason that each stage of sleep is in a particular order and lasts for a particular length.

Research has shown that anemia can result in a disturbance of your sleep cycles (4). The scary thing is that it can have this effect over a long term if you were anemic as a child.

The most notable changes are that there are more periods of REM sleep, and of different durations in those with anemia.

REM sleep is where most insomnia occurs, since it is the easiest stage of sleep to wake up from. So, it’s not surprising if those with anemia tend to have more disturbances during the night.

SummaryAnemia can have long term effects on sleep structure, most commonly resulting in shallower sleep overall.

3. Anemia Can Cause Restless Leg Syndrome, Which Causes Insomnia

Restless leg syndrome is linked to insomnia.

One study showed that people with anemia are 9 times more likely to have restless leg syndrome (5).

If you’re not familiar with the condition:

Restless legs syndrome (RLS) is a condition that causes an uncontrollable urge to move your legs, usually because of an uncomfortable sensation. It typically happens in the evening or nighttime hours when you're sitting or lying down.

RLS has other causes, but iron-deficient anemia is among the most common.

SummaryRestless leg syndrome typically results in difficulty getting to sleep, which has an overlap with insomnia.

4. Depression and Anxiety are Insomnia Risk Factors

Anemic people are more likely to be depressed or have an anxiety disorder.

One study found that 45% of anemia patients had symptoms of at least one of those conditions (6).

That’s a problem since both depression and anxiety are major insomnia risk factors.

All three of these conditions (insomnia, anxiety, and depression) can cause each other, resulting in a vicious cycle that’s hard to get out of.

For example, people with insomnia are more likely to develop depression. People with depression are more likely to develop insomnia.

SummaryAnemia can cause other serious conditions like depression and anxiety disorders, which are both linked to insomnia.

Summary: Does Anemia Cause Sleep Problems?

In short, anemia can quite easily cause sleep problems, and even insomnia.

People with anemia are much more likely to develop insomnia than the general population, and we saw there are 4 possible explanations for why anemia can contribute to sleep issues:

  1. It impairs the function of neurotransmitters that are important for sleep.
  2. It disrupts your built-in sleep structure
  3. It puts you at a higher risk of developing restless leg syndrome (RLS), which in turn can cause insomnia
  4. It puts you at a higher risk of developing depressive or anxiety symptoms, which are both known to cause insomnia.

Anemia is not something to mess around with, if you suspect that it’s causing you sleep issues, go see a doctor. They’ll be able to rule out other possible causes and run tests to confirm if you’re anemic, then recommend iron supplements or another treatment method,


  1. Assessment of subjective sleep quality in iron deficiency anaemia
  2. Association Between Non-Iron-Deficient Anemia and Insomnia Symptoms in Community-Dwelling Older Adults
  3. Iron Deficiency Alters Brain Development and Functioning
  4. Iron deficiency anemia in infancy is associated with altered temporal organization of sleep states in childhood
  5. The prevalence and impact of restless legs syndrome on patients with iron deficiency anemia
  6. Anemia is associated with depression in older adults: results from the InCHIANTI study

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.