High Hemoglobin Levels: Causes, Testing, Treatment, and More

Medically Reviewed By Lauren Castiello, MS, AGNP-C

Hemoglobin is a protein in red blood cells that helps deliver oxygen throughout the body. Some factors, such as smoking and lung disease, can cause high hemoglobin levels in your blood. This may lead to symptoms such as fatigue and swelling. Hemoglobin carries oxygen from your lungs to your tissues and organs through the blood. High hemoglobin levels can affect the health of your blood and circulatory system. However, treatment may effectively address the underlying cause and ease symptoms.

This article discusses high hemoglobin, including symptoms, causes, and testing for high hemoglobin levels. It also explains the treatment and outlook for high hemoglobin.


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Symptoms of high hemoglobin can include: 

Contact your doctor promptly if you notice any symptoms of high hemoglobin levels or any persistent symptoms of illness.

Causes and treatments

Causes of high hemoglobin can include both lifestyle factors and underlying medical conditions, such as Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source :

  • dehydration
  • spending time Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source in an area with high altitude
  • misusing or taking Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source high levels of erythropoietin medication, such as:
    • erythropoietin (Epo)
    • epoetin alfa (Epogen, Procrit)
    • epoetin beta (NeoRecormon)
    • epoetin zeta (Retacrit, Silapo)

Below are some more examples of medical conditions that may lead to high hemoglobin levels, plus their treatments.


Smoking tobacco products can negatively affect health in multiple ways, including your blood health. However, research into the effects of smoking on hemoglobin levels is mixed.

Results from a 2018 study Trusted Source PloS One Highly respected journal, Expert written journal, Peer reviewed journal Go to source suggest that smoking does not affect your hemoglobin levels. However, a 2019 study Trusted Source AHA/ASA Journals Peer reviewed journal Go to source suggests that smoking tobacco may increase your hemoglobin levels in the short term.

Additionally, smoking can increase your risk of heart and lung diseases. This may, in turn, lead to high hemoglobin levels.


If you smoke, your doctor can help you devise a plan to quit smoking. This can include:

  • prescription medications
  • counseling
  • nicotine replacement products

See more advice for quitting smoking.

Treatment of high hemoglobin can vary based on the cause

General treatments for high hemoglobin can include:

  • blood-thinning medication, such as aspirin
  • if necessary, a phlebotomy procedure, which reduces the number of red blood cells using a needle

However, treatment for high hemoglobin can vary based on the underlying cause. As a result, your doctor may recommend a treatment plan that addresses the cause in order to improve high hemoglobin levels.

Cardiovascular and lung conditions

High hemoglobin levels can occur with conditions that affect how effectively oxygen reaches the body’s tissues.

This can include cardiovascular conditions because the heart and blood vessels are responsible for circulating oxygenated blood around the body. It can also include lung conditions since the lungs give oxygen to the blood that the heart moves around the body.

Examples of cardiovascular and lung conditions linked to high hemoglobin include Trusted Source Wiley Peer reviewed journal Go to source :


Treatment for cardiovascular and lung conditions, such as medication and surgery, can depend on the specific condition.

However, certain lifestyle changes may also help improve your cardiovascular and lung health, such as Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source :

Learn more about treatments for cardiovascular diseases and COPD.

Polycythemia vera

Polycythemia vera is a rare blood disorder and type of cancer that can result from genetic mutations. It can cause Trusted Source International Journal of Obesity Peer reviewed journal Go to source high hemoglobin levels, as well as: 

These effects can make the blood thicker and increase the risk of blood clots.


There is currently no known cure for polycythemia vera. However, treatment may help prevent complications and reduce symptoms.

Treatments can include:

Learn more about the causes of and treatments for polycythemia vera.

Testing and results 

A doctor can diagnose high hemoglobin levels using a hemoglobin test. This is usually done during a blood test called a complete blood count (CBC). A CBC can be done as part of a routine health evaluation. Alternatively, your doctor may order this test if you have symptoms of high hemoglobin or other blood disorders

CBC tests measure hemoglobin using grams (g) per deciliter (dL). Standard hemoglobin levels for adults assigned male at birth are 13.5–17.5 g/dL, while the standard range for adults assigned female at birth is 12.0–15.5 g/dL. Having a result above these levels can indicate high hemoglobin.

After diagnosing high hemoglobin, your doctor may request additional exams to determine the cause, such as lung function tests or electrocardiograms. 

Complications and outlook

Without effective treatment, high hemoglobin levels may increase Trusted Source AHA/ASA Journals Peer reviewed journal Go to source the risk of blood clots and related conditions, such as stroke.

As a result, the outlook of high hemoglobin can depend on factors such as:

  • your access to effective treatment
  • the severity of your condition
  • whether you experience any complications, such as stroke

Your outlook can also vary based on the underlying cause of high hemoglobin. This is because related conditions can have varying effects on health.

For example, a 2022 overview Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source suggests that in most cases, treating dehydration can lead to a full recovery. By contrast, polycythemia vera may reduce your life span and have a median survival of around 24 years Trusted Source International Journal of Obesity Peer reviewed journal Go to source .

However, effective treatment can help improve the outlook and health effects of most conditions.

Contact your doctor for individualized advice regarding high hemoglobin and outlook.


Hemoglobin is a protein that helps deliver oxygen throughout your body. However, having a hemoglobin level that’s too high can cause symptoms such as itchy skin, fatigue, and easy bleeding. It may also increase the risk of complications such as stroke.

High hemoglobin can occur due to many factors, including dehydration, cardiovascular conditions, and smoking. As a result, contact your doctor if you experience any symptoms of high hemoglobin, as it may indicate an underlying condition that requires care.

Treatment for high hemoglobin can include medication to thin the blood and phlebotomy to remove excess red blood cells. Treatment approaches can also include addressing the underlying cause.

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Medical Reviewer: Lauren Castiello, MS, AGNP-C
Last Review Date: 2023 Mar 21
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