What is High Hemoglobin?
Hemoglobin (Hb or Hgb) is an iron-containing protein in your red blood cells responsible for transporting oxygen from your lungs to the rest of your body. A high hemoglobin count, also known as polycythemia or erythrocytosis, means you have an excess of this protein in your blood. This can occur when your body produces too many red blood cells or when the concentration of these cells increases due to a decrease in plasma volume.
Typical Hemoglobin Ranges
Normal hemoglobin values can vary slightly by laboratory, but general guidelines exist:
- Adult Males: 13.8 to 17.2 grams per deciliter (g/dL)
- Adult Females: 12.1 to 15.1 g/dL
Levels exceeding these ranges can indicate high hemoglobin and warrant further investigation.
Causes of High Hemoglobin
An elevated hemoglobin count is not a disease itself but a symptom of an underlying condition or environmental factor. The causes can range from simple, temporary issues to serious, chronic diseases.
Lifestyle and Environmental Factors
- High Altitude Living: At higher altitudes, oxygen levels are lower. To compensate, the body naturally produces more red blood cells to improve oxygen delivery, leading to higher hemoglobin levels.
- Smoking: Chronic smoking exposes the body to carbon monoxide, which can interfere with oxygen transport. The body responds by increasing red blood cell production to carry more oxygen.
- Dehydration: When dehydrated, the plasma volume in your blood decreases, concentrating the red blood cells and leading to a falsely elevated hemoglobin reading. This is known as relative polycythemia.
Medical Conditions
- Polycythemia Vera: This is a rare, slow-growing blood cancer in which the bone marrow produces too many red blood cells, as well as an excess of white blood cells and platelets.
- Heart and Lung Diseases: Conditions like chronic obstructive pulmonary disease (COPD), heart failure, and congenital heart disease can cause chronically low blood oxygen levels (hypoxia), prompting the body to produce more red blood cells to compensate.
- Obstructive Sleep Apnea: Interrupted breathing during sleep can cause intermittent hypoxia, which can lead to increased red blood cell production over time.
- Kidney or Liver Cancers: Certain tumors can produce high amounts of erythropoietin (EPO), a hormone that stimulates red blood cell production.
Medications and Therapies
- Performance-Enhancing Drugs: The misuse of erythropoietin (EPO), anabolic steroids, or testosterone replacement therapy can stimulate red blood cell production, leading to elevated hemoglobin levels.
What Happens: Symptoms and Complications
While some people with high hemoglobin may not experience any symptoms, especially if the increase is mild, others may notice several signs related to the thicker blood.
Common Symptoms
- Headaches and dizziness
- Fatigue and weakness
- Blurred vision or vision disturbances
- Shortness of breath
- Itchy skin, particularly after bathing (aquagenic pruritus)
- Reddened skin, especially on the face, hands, and feet
- Joint pain (gout) due to increased red blood cell turnover
- Excessive sweating
Serious Complications
The most significant risk of high hemoglobin is the increased blood viscosity, which makes the blood thicker and slower to flow. This can lead to serious, life-threatening complications.
- Blood Clots: The thickened blood is more likely to form dangerous clots in arteries and veins, which can lead to deep vein thrombosis (DVT) or pulmonary embolism.
- Heart Attack and Stroke: A blood clot can travel to the heart or brain, causing a heart attack or stroke.
- Enlarged Spleen (Splenomegaly): In conditions like polycythemia vera, the spleen may become enlarged as it works harder to filter out excess blood cells.
- Progression to Leukemia: In very rare cases, polycythemia vera can transform into leukemia.
Diagnosis and Management
Diagnosing high hemoglobin begins with a routine blood test called a Complete Blood Count (CBC). If the CBC shows high hemoglobin and hematocrit (the percentage of red blood cells in the blood), a doctor will investigate the cause.
Diagnostic Tests
- Further Blood Tests: These may include checking erythropoietin (EPO) levels, as low EPO can suggest polycythemia vera while high EPO points to other causes.
- Genetic Testing: A blood test can check for a specific genetic mutation (JAK2 mutation) commonly found in people with polycythemia vera.
- Bone Marrow Biopsy: In some cases, a bone marrow sample may be taken to confirm a diagnosis of polycythemia vera.
Treatment Approaches
Treatment is always focused on addressing the underlying cause. Strategies can vary widely depending on the diagnosis.
- Therapeutic Phlebotomy: For conditions like polycythemia vera, blood is regularly withdrawn to reduce the red blood cell count and blood viscosity. This is similar to a blood donation.
- Medication: Low-dose aspirin may be prescribed to reduce the risk of blood clots. Medications like hydroxyurea or ruxolitinib may be used to control blood cell production in polycythemia vera.
- Lifestyle Changes: For high hemoglobin caused by smoking or high altitude, quitting smoking or adjusting altitude can help normalize levels over time.
- Managing Underlying Conditions: Treating the root cause, such as using a CPAP machine for sleep apnea or managing chronic heart or lung disease, is essential.
- Hydration: For dehydration-related high hemoglobin, simply increasing fluid intake is usually sufficient.
High vs. Normal Hemoglobin: A Comparison
| Feature | Normal Hemoglobin | High Hemoglobin |
|---|---|---|
| Blood Viscosity | Healthy, normal flow | Thicker and more viscous |
| Oxygen Levels | Balanced oxygen transport | Can be a sign of the body overcompensating for low oxygen |
| Risk of Clots | Low | Significantly increased |
| Common Symptoms | None | Fatigue, headaches, dizziness, itching |
| Underlying Cause | Generally none, consistent with health | Varies: dehydration, smoking, polycythemia vera, heart/lung disease |
| Typical Treatment | None needed | Varies based on cause; phlebotomy, medication, lifestyle changes |
The Importance of Consultation
If a routine blood test reveals high hemoglobin, it is crucial to consult a healthcare provider for proper diagnosis and management. The approach depends on the cause, and early detection and treatment can help prevent serious complications. For more in-depth information on blood disorders, trusted resources like the Cleveland Clinic offer comprehensive medical insights.
Conclusion
High hemoglobin is a clinical finding that necessitates a thorough medical evaluation. While it can be caused by minor issues like temporary dehydration, it can also point toward serious conditions such as polycythemia vera or chronic heart and lung disease. Elevated hemoglobin increases blood viscosity, raising the risk of dangerous blood clots. Therefore, understanding what happens if hemoglobin is high and working with a doctor to address the root cause is the most effective way to protect your long-term health.
