Does High MCV and MCH Make You Tired? Understanding the Connection

November 17, 2025 •

4 min read

While a blood test showing high MCV and MCH doesn't directly cause fatigue, the underlying health issues they indicate often do. Most commonly, these elevated markers point to a condition known as macrocytic anemia, which can lead to significant exhaustion.

Quick Summary

Elevated MCV and MCH levels are markers for underlying conditions, primarily macrocytic anemia. The associated fatigue is a symptom of this root cause, such as vitamin B12 or folate deficiency, which impairs oxygen delivery.

Key Points

Indirect Cause: High MCV and MCH do not directly cause fatigue; the exhaustion comes from the underlying condition, most often macrocytic anemia.
Macrocytic Anemia: This condition results from enlarged, less efficient red blood cells that fail to transport oxygen effectively, leading to tiredness.
Primary Causes: Common triggers include deficiencies in vitamin B12 or folate, chronic alcohol abuse, and liver disease.
Associated Symptoms: Other symptoms that may accompany fatigue include pale skin, weakness, shortness of breath, and dizziness.
Importance of Diagnosis: It is crucial to see a doctor for testing, as elevated MCV and MCH are a signal that an underlying health issue needs attention.
Effective Treatment: The fatigue can be resolved by addressing the root cause, such as taking supplements for a vitamin deficiency or managing a liver condition.

A complete blood count (CBC) is a standard diagnostic tool that provides crucial insights into a person's health, including the average size and hemoglobin content of their red blood cells. When test results show elevated mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), it's a sign that something is impacting red blood cell production. While the high numbers themselves are not the direct source of weariness, the underlying causes that lead to high MCV and MCH often result in profound fatigue. This is because abnormally large red blood cells, which are less efficient at transporting oxygen, can disrupt the body's energy supply, leaving you feeling constantly tired.

What Are MCV and MCH?

Mean Corpuscular Volume (MCV): MCV measures the average size of your red blood cells. A high MCV reading (known as macrocytosis) means your red blood cells are larger than normal.
Mean Corpuscular Hemoglobin (MCH): MCH measures the average amount of hemoglobin contained within each red blood cell. A high MCH reading is common when MCV is also high, as the larger cells naturally contain more hemoglobin.

The Indirect Link Between Elevated MCV/MCH and Fatigue

Fatigue associated with high MCV and MCH is a direct consequence of the root cause, usually a form of anemia. The red blood cells are produced in the bone marrow, and for them to mature properly, certain nutrients like vitamin B12 and folate are essential. When there is a deficiency, the red blood cells don't mature correctly and are released into the bloodstream while still large and inefficient. This leads to a diminished capacity to deliver oxygen throughout the body, starving your cells of the energy they need and causing generalized weakness and exhaustion.

Common Causes of High MCV and MCH

Several factors can lead to elevated MCV and MCH, and identifying the correct one is key to effective treatment. A thorough review of a patient's history, diet, and habits, along with further lab tests, helps in pinpointing the cause.

Vitamin B12 and Folate Deficiency

This is one of the most common causes of macrocytic anemia. Both vitamin B12 and folate are critical for DNA synthesis in red blood cell production. A deficiency can be caused by:

Poor dietary intake, especially for vegetarians and vegans (B12).
Pernicious anemia, an autoimmune disease that prevents the absorption of vitamin B12.
Gastrointestinal issues like celiac disease or Crohn's disease that impair absorption.

Chronic Alcohol Abuse

Excessive and prolonged alcohol consumption is a frequent cause of macrocytosis. Alcohol can have a direct toxic effect on the bone marrow, hindering red blood cell production. It also interferes with the body's ability to absorb vital nutrients like folate.

Liver Disease

Liver dysfunction, such as cirrhosis, can alter red blood cell membranes, leading to their enlargement and affecting MCV. The damaged liver also has trouble with nutrient processing and absorption, compounding the issue.

Other Medical Conditions

Other potential causes include hypothyroidism, where low thyroid hormones affect red blood cell production; myelodysplastic syndromes, a group of bone marrow disorders; and certain medications, including chemotherapy drugs.

Comparison of Anemia Types

Understanding how different types of anemia affect red blood cells can help clarify why high MCV and MCH lead to fatigue. Here's a quick comparison:


Feature	Macrocytic Anemia (High MCV/MCH)	Microcytic Anemia (Low MCV/MCH)	Normocytic Anemia (Normal MCV/MCH)
Red Blood Cell Size	Larger than normal	Smaller than normal	Normal size
Hemoglobin Content	Higher than average per cell	Lower than average per cell	Normal amount per cell
Common Causes	B12/folate deficiency, alcohol abuse, liver disease	Iron deficiency, thalassemia, chronic disease	Acute blood loss, kidney failure, chronic illness
Associated Fatigue	Common due to inefficient oxygen transport	Common due to insufficient hemoglobin	Common, especially if severe

When to See a Doctor

If you experience persistent fatigue or other symptoms, it's crucial to consult a healthcare provider for proper diagnosis. They will interpret your CBC results and recommend further testing to find the root cause.

If you have ongoing, unexplained fatigue and weakness. Don't assume tiredness is just a normal part of life.
If you experience other symptoms like shortness of breath, pale skin, or dizziness. These are common signs of anemia and should be evaluated.
If you have risk factors such as a vegetarian/vegan diet, a history of heavy alcohol use, or a known gastrointestinal or liver condition.
If your blood test results show abnormal MCV and MCH levels. Even if you have no obvious symptoms, it's a sign that an underlying issue needs to be investigated.

Conclusion

In summary, while high MCV and MCH do not directly cause fatigue, they serve as important indicators for underlying conditions, most notably macrocytic anemia. The fatigue and weakness you may feel are a result of this anemia's impact on oxygen delivery throughout your body. The good news is that with proper diagnosis and treatment, which often involves addressing a vitamin deficiency or another medical issue, your energy levels can be restored. Always consult a medical professional to understand your blood test results and determine the appropriate course of action for your health concerns. For additional information on specific blood disorders, consult an authoritative medical resource, such as the National Institutes of Health.

Frequently Asked Questions

The most common cause is a deficiency in vitamin B12 or folate, which are essential nutrients for proper red blood cell production.

While often related to treatable deficiencies, high MCV can also signal more serious conditions like myelodysplastic syndromes, liver disease, or hypothyroidism, which require further investigation.

Treatment focuses on the underlying cause. If it's a B12 or folate deficiency, supplements are typically prescribed. Other conditions, like liver disease, require specific management.

Without sufficient B12 or folate, the body cannot produce healthy red blood cells. It instead produces larger, less developed, and less efficient red blood cells, which is reflected in high MCV and MCH readings.

Yes, chronic alcohol abuse can interfere with bone marrow function and nutrient absorption, leading to elevated MCV and MCH levels.

Yes, once the underlying cause is properly treated, red blood cell production should return to normal over time, leading to a significant improvement in energy levels and other symptoms.

No, a high MCV alone does not always mean anemia is present, especially if other blood counts are normal. However, it is an important indicator that merits further investigation to understand its cause.