Iron Deficiency and Sleep: A Common Cause of Daytime Fatigue

Few people know of the connection between iron deficiency and sleep. Low iron levels can result in physical fatigue, mental fatigue, and disturbed sleep.

By Nicole Gleichmann

Do you feel tired, weak, and easily distracted? Do you find that no matter how fatigued you are when you hit your pillow, you are unable to get a good night’s rest? Or do you spend far more than the recommended 7 to 8 hours of sleep each night? If you answered yes to one or more of these questions, you might be deficient in iron.

An iron deficiency is a common cause of ongoing fatigue. Because diet and supplements are normally enough to restore iron levels in your body, the solution to your daytime drowsiness may be easier than you could have hoped.

What Is Iron?

Iron is an essential mineral, meaning that humans need to consume iron to survive. It is found in a wide variety of foods, including red meat, legumes, dark green veggies, nuts, and fish.

Iron plays many vital roles in the body. For one, it is involved in the creation of a protein in red blood cells called hemoglobin. Hemoglobin is responsible for transporting oxygen around the body. Oxygen allows cells to function correctly.

Additionally, iron is needed to create certain brain chemicals, including serotonin, dopamine, and noradrenaline. You have likely heard of dopamine and serotonin—they are involved in feelings of reward, excitement, and joy.

Iron Deficiency

Iron deficiency occurs when a negative iron balance exists in the body. The result of this deficiency is a condition called iron deficiency anemia (IDA). IDA is the most common cause of anemia in both developed and developing countries.

Iron deficiency is more common than you might think. In developed countries like the United States and Canada, 1 in 4 adult women have IDA. And 1 in every 2 pregnant women is deficient in iron.

Children, like women, are highly susceptible to IDA and its negative health consequences. Men are less likely to experience iron deficiency. Only around 3% of men in developed countries have IDA.

The 3 Causes of Iron Deficiency

1. Insufficient Dietary Iron Intake

Many people do not consume the RDA (required daily allowance) of iron. This is particularly true for vegans, vegetarians, and those who do not eat a wide variety of whole foods.

Animal foods are the best source of heme iron, the most bioavailable form of iron. High bioavailability means the body more readily uses the iron found in red meat, fish, and poultry than that from plant foods. Because vegans and vegetarians do not eat these foods, they are at a higher risk of insufficient iron consumption than those who do eat meat.

Despite the low bioavailability of the non-heme iron found in plant foods, you can follow a veggie-based diet and get sufficient iron through diet alone. The key is eating a wide variety of healthy, whole foods. Think dark, leafy greens, broccoli, nuts and seeds, whole grains, and legumes, to ensure that you’re getting plenty of vitamins and minerals, including iron.

2. Poor Iron Absorption

For some of us, eating plenty of iron-rich foods may not be enough. There are certain foods and medical conditions that hinder the body’s ability to absorb dietary iron.

Let’s start with food. It is easy to assume that whatever you eat will be utilized by your body. Unfortunately, this is not the case. There is a complicated relationship between the variety of foods that you eat, when you eat them, and what gets absorbed.

Foods that may inhibit iron absorption include:

  • Dairy: Dairy products, such as milk, yogurt, and cheese, are high in a mineral that can block iron absorption: calcium. If you consume high levels of dairy products, it can result in reduced serum iron concentrations. High calcium consumption via dairy products may be one reason why both children and women have high incidences of IDA. Both of these groups are encouraged to consume dairy to boost their intake of calcium.
  • Anti-nutrients: Many foods touted for their impressive health benefits contain compounds that can inhibit iron absorption. Some of these compounds, such as polyphenols and phytates, are antioxidants beneficial for health. However, too many anti-nutrients can negatively impact iron status. Coffee, green tea, black tea, legumes, and whole grains all contain high levels of anti-nutrients.

Certain medical conditions can inhibit iron absorption. Digestive disorders are the most common of these. Conditions like Crohn’s disease and irritable bowel disease are marked by damage to the gastrointestinal tract. Sometimes, this damage can reduce the body’s ability to absorb nutrients, such as iron, from the foods that you eat.

Thyroid disorders can also impact nutrient absorption. A result of hypothyroidism (an underactive thyroid) can be low levels of stomach acid. The consequence is a lessened ability to break down and absorb dietary iron.

3. High Iron Utilization

In some circumstances, our bodies can require high amounts of iron. When iron stores are rapidly depleted, a standard diet may be unable to keep up with the increased demand for iron, leading to a deficiency. When demand exceeds supply, you can experience anemia.

Heavy Monthly Flow

One of the most common sources of iron depletion? Heavy periods. Women who experience a heavy flow lose a lot of blood. Their bodies require sufficient iron stores when restoring the lost blood. When there isn’t enough iron, a woman can become anemic. With periods happening roughly every month, some women will be unable to recover quickly enough, and they will become anemic.


Athletes are also at an increased risk of IDA. Iron helps muscles use and store oxygen. When you exercise, muscle cells require more oxygen to create the power output needed to do things like run or lift weights. Many studies have found athletes to be at an increased risk of IDA. The harder and more frequently you work out, the higher your risk of iron deficiency.


When a woman is pregnant, her body must create more blood than it usually would. The fetus needs a constant supply of blood to deliver the oxygen and nutrients that it needs to grow and develop. Because the body needs more iron to create the hemoglobin in red blood cells, pregnant women have a very high need for dietary iron.

Growth and Development

There is one period in each of our lives where our bodies demand a high amount of iron: development. From the moment we are born to the moment that we stop growing, our bodies require high levels of iron to keep oxygen supply up for our growing bodies. Without it, our physical growth and cognitive development can suffer.

What Are Common Signs of Iron Deficiency?

When your body has a negative iron balance, your cells do not receive adequate oxygen, and your brain produces fewer neurotransmitters. As a result, you may experience the following symptoms.


Feelings of physical lethargy and mental sluggishness are common symptoms of IDA. A result can be difficultly exercising, reduced reaction time, impaired cognition and memory, brain fog, general sleepiness, and more. You may feel like your body is weighed down, and your mind is frustratingly slow.

Apathy, Anxiety, and Depression

Iron is needed to create brain chemicals known as neurotransmitters. In particular, iron is necessary for the synthesis of dopamine and serotonin, neurotransmitters that play a central role in mood. A neurotransmitter deficiency can lead to feelings of boredom, apathy, stress, anxiety, and depression.

Disordered Sleep

Many people who are deficient in iron can experience trouble sleeping well throughout the night. Consequently, they often sleep excessively long hours in an attempt to make up for poor sleep quality. This may be a result of reduced monoamine synthesis, brain chemicals involved in our sleep-wake cycle.

Hair Loss and Dry Skin

When your body experiences a shortage of oxygenated blood caused by insufficient iron, it chooses wisely where this oxygen will be delivered. Your internal organs, lungs, and brain are far more critical for your survival than your hair or skin.

As a result, the appearance of your skin and hair are often the first physical clues that you need more iron. You may experience dry, brittle hair and skin. Eventually, an iron shortage can result in hair loss.

Shortness of Breath and Irregular Heartbeat

We all experience shortness of breath and a racing heart at one time or another. But if you notice that easy tasks are making you gasp for air as you feel your chest pounding, it might be due to a lack of oxygen in your blood.

When you lack iron, your blood will contain less oxygen. Consequently, your heart must pump faster to deliver sufficient oxygen to your muscles. As your heart beats faster, you will need to breathe heavier to acquire oxygen from the air.

Increased stress on your heart can lead to an irregular heartbeat, heart palpitations, and, eventually, a heart attack.

If you find that activities like walking briskly or climbing are more challenging than they used to be, it might be due to an iron deficiency.

Dizziness and Headaches

When iron deficiency results in low levels of oxygen in the blood, the arteries in the brain can swell. This swelling, combined with the lack of oxygen, leads to symptoms like headaches, lightheadedness, and dizziness. You may also notice tinnitus, or ringing in your ears.

Restless Leg Syndrome

Restless leg syndrome (RLS) is a condition where people have trouble keeping their legs still when they lie down. RLS can make getting a good night’s sleep next to impossible. Scientists have found that decreased iron levels exacerbate RLS symptoms.

Reduced iron concentrations can result in decreased dopamine production as well as depressed levels of iron in the brain. These factors are believed to be involved in the pathogenesis of RLS. Some people with RLS will experience a reduction, or even resolution, of their symptoms upon fixing their iron insufficiency.

Other Symptoms

There are a variety of other symptoms that those deficient in iron may experience:

  • Odd cravings for things like dirt or ice
  • Pale or itchy skin
  • Red, sore, or smooth tongue
  • Brittle or spoon-shaped fingernails
  • Irregular menstruation
Woman Suffering From Depression laying on bed, Bed , Sleep Disorders, Insomnia

The Link Between Iron Deficiency and Sleep

The relationship between daytime fatigue and sleep is complicated. Many people who experience daytime fatigue are merely feeling tired from a night of not sleeping well.

But there is something unique about the relationship between iron deficiency, daytime fatigue, and sleep. People who need more iron are unable to get enough rest to feel energized the following day.

If you find that no amount of sleep results in feeling well-rested, a lack of iron could be to blame.

A lack of sleep doesn’t directly cause the lack of energy that you experience with an iron deficiency. Instead, it results from a lack of oxygen delivered to cells throughout your body — particularly to those in your brain and muscles.

This fatigue can make exercise difficult. You will find yourself out of breath easily and may experience an inability to muster up the energy to push yourself as hard as you would like to. Your brain, too, will feel fatigued. When you try to concentrate or think deeply, you may feel like you are utterly incapable of doing so.

Another common symptom of iron insufficiency is an inability to fall asleep or sleep well through the night in spite of extreme fatigue. One theory as to why people who are deficient in iron experience insomnia is a decrease in the metabolism of key sleep chemicals.

As we covered above, iron is necessary for the synthesis of brain chemicals called neurotransmitters. These chemicals are involved in sleep physiology. What this means is that too little iron may directly result in disturbed sleep. This may include difficulties falling asleep, trouble sleeping through the night, or possibly a lack of deep, restorative sleep.

With the multifaceted roles of iron in sleep and energy, it makes sense that excessive fatigue and difficulty sleeping are common symptoms. It is often unmanageable fatigue that leads people to seek out their doctor’s advice.

Treating an Iron Deficiency

Many women can relate to feelings of fatigue, stress, depression, and trouble sleeping. With the ever-increasing demands that we face as we balance work and life, it is only natural to feel these things at one time or another.

But with 1 in 5 women experiencing iron deficiency anemia (IDA), there is a good chance that your ongoing fatigue has a cause and a solution.

If you find yourself experiencing multiple symptoms of iron deficiency, talk to your doctor. They can conduct a test to determine your iron levels, known as a serum ferritin test. Once you know your iron status, you and your healthcare professional can develop a plan to get you on the path to health and wellness.

Eating an Iron-Rich Diet

The first step to achieving a positive iron balance is consuming enough iron through your diet. Many people, whether omnivores or herbivores, will find that they can boost their iron levels to where they need to be by simply eating more iron.

Try adding in more of these iron-rich foods:

  1. Red meat
  2. Fish
  3. Poultry, like chicken or turkey
  4. Eggs
  5. Dark, leafy green veggies
  6. Broccoli
  7. Beans, lentils, and other legumes
  8. Nuts and seeds
  9. Whole grains

You may notice that these foods fall into almost every food group. The fact is, most people who consume a balanced diet rich in whole foods will get all of the iron that they need from their diet. It is when you replace healthful foods with processed food and fast food that you are more likely to experience an iron deficiency.

Reducing Anti-Nutrients

You may find that your iron levels increase more rapidly when you reduce your consumption of dietary components that can decrease iron absorption. Dairy, coffee, and tea are three types of beverages that can inhibit iron absorption.

Dairy is high in calcium, and many people consume far more dairy than they need to. The calcium in dairy decreases your body’s ability to absorb iron. The idea here is that there is too much of a good thing. Try to avoid consuming dairy morning, noon, and night to amp up your iron levels.

Similarly, anti-nutrients found in common drinks like coffee and green or black tea can reduce iron absorption. Rather than cut these drinks out completely, try to limit their consumption. For example, if you are eating an iron-rich meal, opt for water rather than coffee or tea.

Consuming More Vitamin C

Vitamin C can increase how much iron your body absorbs. Add in foods rich in vitamin C to reap this benefit. Some of the best options include:

  1. Citrus fruits (oranges, limes, lemons)
  2. Yellow, green, red, or orange peppers
  3. Kiwi
  4. Dark, leafy greens
  5. Strawberries
  6. Tomatoes
  7. Broccoli
  8. Cauliflower
  9. Sweet potato

Taking an Iron Supplement

When diet alone isn’t enough, you may need to turn to iron supplementation. But be cautious—there are dangers associated with excess iron consumption. Before you decide to supplement with iron, speak with your doctor. They can help you determine the appropriate supplemental dosage. This can vary greatly depending on factors like sex, age, diet, health status, whether you are pregnant or breastfeeding, and more.


Combine extreme mental and physical fatigue with trouble sleeping at night, and you might be experiencing the symptoms of iron deficiency. Simple dietary changes may be all you need to feel like yourself again. But if lifestyle changes don’t work, speak with your doctor. They can test for an iron deficiency and formulate a treatment plan. This may include lifestyle changes, treatment for an underlying health condition, iron supplements, or more.

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