From the Guidelines
Elevated hemoglobin levels, or polycythemia, can be caused by several factors, including dehydration, high altitude, smoking, lung diseases, heart conditions, genetic disorders like polycythemia vera, and certain medications such as testosterone or erythropoietin therapy. The most common causes of high hemoglobin levels include:
- Dehydration, which concentrates blood components
- Living at high altitudes, where lower oxygen levels stimulate red blood cell production
- Smoking, which reduces oxygen availability in the blood
- Certain lung diseases like COPD that decrease oxygen levels
- Heart conditions that affect blood oxygenation
- Genetic disorders like polycythemia vera, where bone marrow produces too many red blood cells Some medications, such as testosterone or erythropoietin therapy, can also increase hemoglobin production 1. Less commonly, kidney diseases, liver diseases, or certain tumors that produce erythropoietin may be responsible 1.
The body increases red blood cell production primarily as a compensatory mechanism when tissues need more oxygen. For example, at high altitudes, the body produces more red blood cells to compensate for the lower oxygen levels, resulting in increased hemoglobin levels 1. If you have unexplained elevated hemoglobin, medical evaluation is important as treatment depends on identifying and addressing the underlying cause, which might include lifestyle changes, medication adjustments, or specific treatments for conditions like polycythemia vera.
It is essential to note that an increase in hemoglobin levels can be a normal response to certain conditions, such as high altitude, but it can also be a sign of an underlying disease or disorder. Therefore, it is crucial to consult a healthcare professional for proper evaluation and treatment. The diagnostic approach to polycythemia involves determining whether the diagnosis should be suspected based on factors such as hemoglobin/hematocrit level, documented increase in hemoglobin/hematocrit level, or presence of polycythemia-related features 1.
In summary, elevated hemoglobin levels can be caused by various factors, and a thorough medical evaluation is necessary to determine the underlying cause and develop an appropriate treatment plan. The most critical step in managing elevated hemoglobin levels is to identify and address the underlying cause, which may involve lifestyle changes, medication adjustments, or specific treatments for conditions like polycythemia vera.
From the Research
Causes of High Hemoglobin
- High hemoglobin levels can be caused by various factors, including obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) 2.
- The prevalence of polycythemia, a condition characterized by high red blood cell count, is higher in patients with OSA and COPD compared to those with COPD alone 2.
- The severity of OSA, measured by the apnea-hypopnea index (AHI), is not directly associated with hematocrit or clinically significant erythrocytosis, but rather with nocturnal hypoxemia 3.
- Nocturnal hypoxemia, measured by awake and mean nocturnal oxygen saturation, is inversely proportional to hematocrit and is a predictor of erythrocytosis 3.
- Chronic intermittent hypoxia (CIH) in OSA can lead to increased expression of inflammatory stress markers and endothelial dysfunction, which may contribute to high hemoglobin levels 4.
- Higher hemoglobin levels within the normal variation are associated with an adverse metabolic profile, increased prevalence of key components of metabolic syndrome, and higher risk for cardiovascular disease-related and total mortality 5.
Associated Factors
- Active tobacco use, increased alcohol ingestion, and exogenous testosterone therapy are associated with higher hematocrit levels 3.
- Percentage of total sleep time with SaO2 <90% (TS90) is an independent factor for polycythemia, especially in GOLD grade 1-2 COPD patients 2.
- Higher hemoglobin levels are associated with higher leptin levels, lower adiponectin levels, and lower plasma ghrelin levels 5.