Normal Hemoglobin Levels
A normal hemoglobin level for women ranges between 12 to 16 g/dL, whereas it is 14 to 17.4 g/dL for men and 9.5 to 24.5 g/dL for children, depending on their age. However, a physiological increase or decrease in normal hemoglobin limits could be attributed to factors like pregnancy, full-term infancy, smoking, altitude, and even ethnicity.
How many times have you been to a doctor for tiredness and he suggested you could be low on hemoglobin? Hemoglobin (Hb or Hgb), the protein molecule in the blood that gives it the rich red color is a vital source of iron in the body.1 It plays an important role in transporting oxygen from the lungs to the body tissues.2 Needless to say, abnormal levels of hemoglobin can cause various health disorders.
What Causes Hemoglobin Levels To Drop Or Hike Up?
As far as the relationship between hemoglobin levels and diseases go, it’s a two-way street. A drop in hemoglobin levels can lead to a lot of diseases. At the same time, many critical illnesses like cancer, kidney, and liver complications can cause the hemoglobin levels to drop. Anemia, a classic sign of low hemoglobin level is prevalent in many critically ill patients.3
Your hemoglobin levels can also drop due to blood loss from wounds (both internal and external) and frequent blood donations. In women, heavy menstrual bleeding can result in low hemoglobin levels.4
High hemoglobin levels, though very rare, can be caused by health conditions like polycythemia, heart failure, and chronic obstructive pulmonary disease.5 There are two non-pathological reasons for elevated hemoglobin levels–when you are at an elevated altitude where the oxygen supply is less and if you are a smoker.6
What Happens When There Is A Drastic Change In Hemoglobin Levels?
If the hemoglobin levels drop drastically, it leads to anemia. Tiredness is one important sign of anemia due to the lack of oxygen supply to the body’s organs and tissues. If anemia is left unchecked, it can lead to shortness of breath and/or exercise intolerance—a condition where a person becomes easily fatigued during or after physical activities. It can also result in the failure of heart and other vital organs.7 Anemia also makes you prone to many infections. Some cases of restless leg syndrome are also caused by anemia due to iron deficiency.8
Pregnancy is a time when you hear a lot about maintaining adequate hemoglobin levels. That’s because pregnancy can cause regular fluctuations in hemoglobin levels that could prove dangerous if left unchecked. A study has shown that seriously low hemoglobin levels during pregnancy can result in severe morbidity or mortality of the fetus. Though epidemiological studies have concluded that high hemoglobin levels are not directly responsible for any adverse outcomes during pregnancy,9 there are studies that have found an association between high maternal hemoglobin concentrations and an increased risk of poor pregnancy outcomes. Like this one. A study conducted on a very small group of just 24 pregnant women showed that the high viscosity of the mother’s blood from high hemoglobin levels could impede the uteroplacental circulation (circulation of blood between the uterus and the placenta) that could lead to adverse outcomes including fetal death.10
What Is Normal Hemoglobin Level?
This takes us to the most crucial question: What is normal hemoglobin level? To know your hemoglobin level, you need to head to a lab to take a blood test. The result will show the hemoglobin measurement in grams per deciliter (g/dL). Normal hemoglobin is different for men, women, and children.
Here are the approximate normal values11:
|Men||14 to 17.4 g/dL|
|Women||12 to 16 g/dL|
- 9.5 to 24.5 g/dL for children, depending on the child’s age.
Though this is considered to be the standard hemoglobin level, there are certain variables.12 Here’s the list:
Full-term Infants: The hemoglobin level of a human being is at its highest at birth, perhaps from the fetal adaptation to the oxygen-deficient environment of the uterus. The level, however, drops drastically hitting the lowest at 2 months. Then it gradually picks up till 6 months after which it levels out.
Pregnancy: During pregnancy, both plasma volume and red cell mass expand, resulting in diluted hemoglobin. Even in women with adequate iron nutrition, the hemoglobin concentration is found to fall from the early part of the first trimester, reaching its lowest level near the end of the second trimester. It, however, picks up during the third trimester.
The normal hemoglobin concentration in the trimesters of pregnancy are 11-13 g/100 ml, 10-13 g/100 ml and 11-14 g/100 ml, respectively.13
Ethnicity: Ethnicity too plays a role in hemoglobin levels. Data from the USA show that the healthiest African Americans have a hemoglobin count 5-10g/L less than that of the whites. Other US-based races–East Asians, Hispanics, Japanese, and American Indians–have hemoglobin values similar to that of white Americans.
Smoking: Smokers have higher hemoglobin levels than non-smokers. But this is nothing to be proud about because the carbon monoxide that gets inhaled from cigarettes results in increased carboxyhemoglobin, which has no oxygen-carrying capacity. Hemoglobin levels increase to adjust to this change.
Altitude: In higher altitudes (above 1000 m), hemoglobin concentration in blood increases. This is an adaptive response to reduced oxygen level at that altitude. The increased red cell production ensures that sufficient oxygen is supplied to the tissues.
Why Are Hemoglobin Levels In Men And Women Different?
Men have more hemoglobin or red blood cells in their blood than women but this is not a phenomenon restricted to humans. A similar sex-related difference is seen in many mammals, birds, and reptiles, too. Certain studies have concluded that it could be a direct effect of the sex hormones–estrogens and androgens–on red blood production or erythropoiesis.14
Some other studies, however, say there is more to it than meets the eye. It has been found that the hemoglobin levels of prepubertal girls, as well as women after 10 years of menopause, are the same as their male counterparts which clearly points at the role of menstruation in determining the hemoglobin levels in women. The study has also shown that almost 90 percent of women in the UK do not have their daily recommended intake of iron from their diet.15
There are various ways to keep your hemoglobin levels normal, adequate nutrition being one. If you are anemic, your doctor could also suggest supplements or ways to get over it depending on the cause of the anemia. So do not leave that tiredness or paleness of the skin unchecked for long.
References [ + ]
|1.||↑||Hemoglobin And Functions Of Iron. UCSF.|
|2.||↑||Yandamuri Ayyanna, Yandamuri Narayudu, “Survey on Haemoglobin level in the different age groups of male and female human beings living in the rural and urban area”.Int.J.Ph.Sci., May-August,2013;592):-2086.|
|3.||↑||Fakhry, Samir M., and Paola Fata. “How low is too low? Cardiac risks with anemia.” Critical Care 8, no. 2 (2004): S11.|
|4.||↑||Iron Deficiency Anemia-Causes. NHS.|
|5, 11.||↑||Hemoglobin. URMC.|
|6, 9.||↑||Yip, Ray. “Significance of an abnormally low or high hemoglobin concentration during pregnancy: special consideration of iron nutrition.” The American journal of clinical nutrition 72, no. 1 (2000): 272s-279s.|
|7.||↑||Anemia Of Inflammation And Chronic Disease. NIDDK.|
|8.||↑||Iron Deficiency Anemia-Complications. NHS.|
|10.||↑||Larsen, Sandra, Elisabeth Krefting Bjelland, Camilla Haavaldsen, and Anne Eskild. “Placental weight in pregnancies with high or low hemoglobin concentrations.” European Journal of Obstetrics & Gynecology and Reproductive Biology 206 (2016): 48-52.|
|12.||↑||Adjusting Hemoglobin Levels In Program Surveys. INACG.|
|13.||↑||Haram, K., T. Hervig, and R. J. Ulvik. “Hemoglobin, iron deficiency and anemia in pregnant women. Diagnostic aspects.” Tidsskrift for den Norske laegeforening: tidsskrift for praktisk medicin, ny raekke 117, no. 7 (1997): 962-966.|
|14.||↑||Murphy, William G. “The sex difference in haemoglobin levels in adults—mechanisms, causes, and consequences.” Blood reviews 28, no. 2 (2014): 41-47.|
|15.||↑||Rushton, D. Hugh, Robin Dover, Anthony W. Sainsbury, Michael J. Norris, Jeremy JH Gilkes, and Ian D. Ramsay. “Why should women have lower reference limits for haemoglobin and ferritin concentrations than men?.” BMJ: British Medical Journal 322, no. 7298 (2001): 1355.|