Oxygen is the indispensable primal driver of the respiratory process that sustains life. A component of red blood cells, hemoglobin is the specialized protein that makes oxygen transportation from the lungs to every cell possible. Any value above 17.2 gm/dL for males and 15.1 gm/dL for females is considered to be an elevated hemoglobin count. This article delves into the causative factors behind occurrence of high hemoglobin levels in the human body. Let's first understand the exact function of this iron-containing protein.

Role Played by Hemoglobin

Hemoglobin is a metalloprotein molecule making up 35% of the total weight of every red blood cell in the human body. It performs the important function of transporting oxygen from lungs to cell tissues of the body (in its oxygen-binded form being known as Oxyhemoglobin, with the oxygen binding with the iron or heme part) and brings back the carbon dioxide from cell tissues (known in its carbon dioxide-binded form as carbaminohemoglobin) back to the lungs for exhalation. It also transfers nitric oxide through the blood. The presence of iron grants blood its characteristic red tint.

Normal Levels

The hemoglobin content of blood varies according to age. It is an important indicator of overall health of the blood circulatory system. Here is a list of normal hemoglobin levels in humans according to age groups. The levels are measured in gm/deciliter (gm/dl) and normal levels are as follows:

High Hemoglobin Levels
Newborn babies17 - 22 gm/dL
Babies aged 1 week15 - 20 gm/dL
Babies aged 1 month11 - 15 gm/dL
Children11 - 13 gm/dL
Men13.8 - 17.2 gm/dL
Women12.1 - 15.1 gm/dL
Pregnant Women11 - 12 gm/dL
Men aged more than 50 years12.4 - 14.9 gm/dL
Women aged more than 50 years11.7 - 13.8 gm/dL


Generally, a count greater than 17.2 gm/dL is a high value, possibly pointing towards a physiological anomaly. Some of the prime symptoms indicating elevated levels of hemoglobin are slowed down mental functioning and bluish discoloration of fingers and toes. Here are some of the possible causes.

High Altitudes

It has been observed that people living in high altitude locations have high levels of hemoglobin. The rarefied atmosphere necessitates the higher count, to maintain sustainable levels of oxygen. It is an adaptive feature of the human body as it adjusts itself according to environmental requirements.


Smoking is another causative factor which may elevate levels of this protein. This is caused by a physiological response of the body to low levels of oxygen intake while smoking.


Dehydration causes a temporary rise in hemoglobin levels due to less dilution of blood. The body adjusts the hemoglobin values back to normal levels, after it is adequately re-hydrated.

Lung Diseases like Emphysema

Emphysema is a lung disease which destroys the exchange mechanism in lungs that enables mixing of oxygen in the blood. Subsequently the body is deprived of oxygen, which causes the level of hemoglobin to shoot up. Along with chronic bronchitis these medical conditions are known as chronic obstructive pulmonary disease (COPD).

Certain types of tumors may also cause hemoglobin to rise higher. These tumors may be in any part of the body. The exact mechanism by which tumors are linked to hemoglobin is not known. However, there is a definite correlation between the two.

Polycythemia Rubra Vera

Polycythemia Vera is a disease which causes a proliferation in number of red blood cells of the body and subsequently high levels of hemoglobin. People affected with polycythemia have blood hemoglobin levels equal to or higher than 18.5 gm/dL.

Pulmonary Fibrosis

A scarring of the lungs due to excess growth of fibrous connective tissue leads to pulmonary fibrosis, that may cause hemoglobin levels to rise in response to lack of oxygen. Shortness of breath after prolonged physical effort is a prominent symptom of this disease.

Performance Enhancement Drugs

Certain performance enhancement drugs used by athletes, if consumed in excess, can cause hemoglobin proliferation in the blood. One example of such a drug is Erythropoietin. Use of anabolic steroids may also raise levels.

Extreme Physical Exertion

High levels of this protein in the blood may also be a result of being subjected to excessive physical effort. A bout of vomiting that makes one lose body fluids might also cause elevation in levels.

High levels of hemoglobin could be indicative of certain diseases or simple adaptive metabolic responses. A blood test can accurately determine anomalous levels. It should be noted that standard values for hemoglobin levels tend to vary across lab results; largely being a function of individual physiology.

Disclaimer: This article is for reference purposes only and should not be taken as a substitute for advice from a certified medical practitioner.