A high hemoglobin level means you have an above-normal amount of the protein in red blood cells that delivers oxygen throughout your body and brings carbon dioxide back to the lungs. When the body needs more oxygen than it is getting, hemoglobin levels rise to fix that.

High hemoglobin is often caught during routine blood tests. It may be due to lifestyle factors, like smoking or living in a high altitude, or medical conditions that promote low blood oxygen, like heart failure. Diseases that increase red blood cell production can also be to blame.

This article looks at the symptoms and causes of high hemoglobin levels, how it’s diagnosed and treated, and what lifestyle changes might help keep your levels in the normal range.

Symptoms of High Hemoglobin

High hemoglobin levels themselves usually don’t cause any symptoms. Sometimes, they may cause:

  • HeadachesDizzinessSymptoms of the condition causing high hemoglobin

The symptoms of the underlying cause of high hemoglobin can, of course, vary.

Complications of high hemoglobin can be serious. They include:

  • Heart attack
  • Stroke
  • Blood clots

Causes of High Hemoglobin

Several lifestyle issues and medical conditions can cause high hemoglobin levels.

Many conditions that lead to high hemoglobin are chronic. It’s possible that you may be diagnosed before getting an abnormal hemoglobin test result.

Lifestyle Issues

Lifestyle causes of elevated hemoglobin levels include: 

  • Smoking: Red blood cells and hemoglobin increase to compensate for high levels of carbon monoxide in cigarette smoke.
  • High altitude: Lower oxygen pressure in your environment makes your body require more hemoglobin to maintain your oxygen needs.

Sometimes, dehydration can give you false high hemoglobin results when levels are normal. This is believed to be because dehydration changes the amount of fluid in your blood. Rehydrating usually corrects the measurement. 

Medical Conditions

These conditions can make your body produce excess red blood cells, and high hemoglobin is a consequence of that: 

  • Chronic low oxygen level
  • Chronic obstructive pulmonary disease (COPD) (a group of chronic, inflammatory lung diseases that includes emphysema)
  • Heart failure
  • Kidney disease
  • Liver or kidney cancer
  • Polycythemia vera (a blood disorder)
  • Erythropoietin (a kidney hormone that stimulates red blood cell production and is used to treat some medical conditions; it is sometimes misused to enhance athletic performance)

Diagnosing High Hemoglobin

High hemoglobin levels show up in a blood test that’s part of a routine complete blood cell count (CBC).

You’ll be sent for a simple blood draw, where a healthcare professional will collect blood in a syringe and send it to a laboratory for testing.

Normal hemoglobin values vary slightly depending on the lab. Hemoglobin is usually reported in grams per deciliter (g/dL).

Treatment of High Hemoglobin

The treatment for a high hemoglobin level depends on the cause. You may just need treatment for the underlying condition, or you may need additional treatment for the high hemoglobin.

High hemoglobin, especially in polycythemia vera, is often treated with therapeutic phlebotomy. That involves removing a unit of blood (similar to making a blood donation). This may need to be done several times.

High hemoglobin is also treated with medication to reduce the number of red blood cells, which can decrease the effects and complications of the condition.

Diet and Lifestyle Changes

If you have high hemoglobin, it’s important that you maintain a healthy diet. No specific dietary recommendations have been established, the following are good guidelines to follow:

  • Stay hydratedAvoid alcoholAvoid foods that are high in sugar or fatEat an ample amount of fruit, vegetables, and lean protein

Summary

Elevated hemoglobin doesn’t usually cause symptoms, but it can cause complications, including blood clots. A high hemoglobin level is often an indicator of disease, including polycythemia vera, cancer, heart disease, lung disease, and kidney or liver disease.

Smoking and high altitudes can also cause hemoglobin levels to increase.

Hemoglobin levels can be checked with a routine blood test. Treatment is usually necessary for the underlying cause, and sometimes treatment is specifically needed for high hemoglobin levels as well.

Frequently Asked Questions

  • What can I do if my hemoglobin is high?
  • If you smoke, stop. And make sure you stay hydrated and eat a healthful diet. And be sure to follow up with your healthcare provider and get any additional tests they suggest. Once the cause of your high hemoglobin is determined, proper treatment can be prescribed.
  • Learn More:
  • Quit-Smoking Aids
  • Are there any medications that can cause high hemoglobin?
  • Erythropoietin is a medication that can be used to raise red blood cells if they are low. Misuse can cause high hemoglobin levels.
  • Does dehydration cause high hemoglobin?
  • No, but dehydration can give you a false high hemoglobin reading on a blood test. This is because it lowers the fluid volume in your blood relative to red blood cells, which contain hemoglobin.
  • Learn More:
  • Preventing Dehydration
  • What could happen if my hemoglobin level gets too high?
  • Having a high red blood cell concentration could increase your risk of blood clots. If your hemoglobin is high due to chronic illness such as cancer or kidney disease, that disease may continue to progress and cause health problems until it is treated.
  • Learn More:
  • How Blood Clots Are Treated

If you smoke, stop. And make sure you stay hydrated and eat a healthful diet. And be sure to follow up with your healthcare provider and get any additional tests they suggest. Once the cause of your high hemoglobin is determined, proper treatment can be prescribed.

Erythropoietin is a medication that can be used to raise red blood cells if they are low. Misuse can cause high hemoglobin levels.

No, but dehydration can give you a false high hemoglobin reading on a blood test. This is because it lowers the fluid volume in your blood relative to red blood cells, which contain hemoglobin.

Having a high red blood cell concentration could increase your risk of blood clots. If your hemoglobin is high due to chronic illness such as cancer or kidney disease, that disease may continue to progress and cause health problems until it is treated.

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By Heidi Moawad, MD

Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.