A low hemoglobin count is referred to as anemia or a low red blood count. Many factors can contribute to low hemoglobin levels, including iron deficiency, blood loss due to injury or illness, liver problems, some types of cancer, and physiological changes such as pregnancy or growth spurts in children.
A slightly low hemoglobin level isn't necessarily a concern — some people have naturally low hemoglobin counts without any underlying cause. However, significantly low hemoglobin levels can lead to serious health issues, including heart problems and death. But how low can hemoglobin go before death occurs?
This article will explore how low your hemoglobin count can go before causing death. We'll also look at some things you can do to prevent your hemoglobin levels from getting dangerously low. Read on.
We make it easy for you to participate in a clinical trial for Anemia, and get access to the latest treatments not yet widely available - and be a part of finding a cure.
Hemoglobin is a protein found in red blood cells (RBCs). This protein attracts oxygen molecules to the red blood cells for transportation from your lungs to the whole body. Hemoglobin is also responsible for the bright red color we've come to associate with oxygenated blood.
Each hemoglobin protein is made up of distinct units called hemes. The hemes can attach to iron molecules, and the iron binds to oxygen. The interaction between iron and oxygen makes blood appear bright cherry red.
An individual's hemoglobin count indicates the oxygen-carrying capacity of the red blood cells. Hemoglobin level is measured in grams (gm) per deciliter (dL) of whole blood. One decilitre is equal to 100 milliliters.
The normal range varies from person to person, based on factors such as age and gender — starting in adolescence. The normal hemoglobin range for men is 14–18 g/dl and 12–16 g/dl for women. Usually, a person's hemoglobin count is considered low if it's below the normal range.
Low levels of hemoglobin are relatively common across the general population. Although rare, a high hemoglobin count can occur when your body requires an increased oxygen-carrying capacity. Various factors, including high altitude residency, smoking habits, and pregnancy status, can influence hemoglobin levels.
Hemoglobin levels are typically evaluated through the complete blood count (CBC) test. CBC is a routine test your healthcare provider may order to help diagnose various conditions, including infections, anemia, and leukemia. A hemoglobin count that's either too low or too high can adversely affect your health.
Your hemoglobin level is considered low if it's below the normal range. Slightly low hemoglobin is probably nothing to worry about. However, a severely low hemoglobin count, which generally results in a condition known as anemia, can have adverse effects on your health.
Your hemoglobin levels may be low for several reasons. Some of the more common culprits of low hemoglobin are:
Poor diet. You are not getting enough essential nutrients such as iron, folate, and certain B vitamins from your diet. Not enough iron in your diet can lead to iron deficiency anemia.
Blood loss. Losing a massive amount of blood due to a traumatic injury or illness can cause low hemoglobin. Women may also have low hemoglobin levels due to heavy menstrual bleeding.
Major physiological changes. Your body has undergone major changes recently, such as pregnancy or a growth spurt in children and teenagers.
Intestinal bleeding. There's bleeding in your gut due to a stomach ulcer or colon cancer. Overusing nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may cause bleeding in your GI tract.
Abnormal hemoglobin structure. In people with hemoglobin disorders such as sickle cell disease and thalassemia, red blood cells are misshapen and fewer in number. Faulty red blood cells are destroyed in large numbers and are not adequately replaced, resulting in low hemoglobin levels.
Bone marrow problems. You have a condition that affects your bone marrow's ability to produce or support enough red blood cells (RBCs). Here are some of the illnesses and other factors that affect RBC production:
Chronic kidney disease
Leukemia (blood cancer)
Lymphoma (cancer that affects the lymphatic system)
If an underlying condition affects your body's ability to produce red blood cells, your hemoglobin count may drop significantly. A low hemoglobin count means your organs and tissues are not getting enough oxygen, resulting in a plethora of symptoms.
Here are some of the more common symptoms of low hemoglobin:
Fatigue or getting tired quickly
Pale or yellow skin, gums, and nails
Swollen feet, hands, or both
Feeling lightheaded, dizzy, or weak
Fast breathing or shortness of breath
Fast or unusual heartbeat (tachycardia)
Note that individuals with low hemoglobin experience symptoms differently. Sometimes, symptoms can be so mild that you might not notice them. If you are experiencing symptoms that may be linked to low hemoglobin levels, consult your healthcare provider immediately.
Hemoglobin is necessary for the survival of a human being. Without sufficient hemoglobin, the body cannot efficiently transport oxygen from the lungs to tissues and cells. Your heart pumps more blood to compensate for the low oxygen levels.
Because low hemoglobin makes the heart pump harder than usual, it can worsen cardiac function due to increased stroke volume and cardiac stress through tachycardia. Overexertion of the heart due to low hemoglobin can lead to complications such as heart failure, which can lead to death.
Much of the research into low hemoglobin and cardiovascular health has focused on iron deficiency, which can cause low hemoglobin and its effects on the heart. Studies show that severe iron deficiency can damage the left ventricle, which is known as left ventricular (LV) dysfunction, causing overt heart failure.¹
Normal hemoglobin levels vary from person to person based on factors like age and gender. For men, a normal hemoglobin level ranges between 14–18 g/dl. For women, a regular normal range is 12–16 g/dl.
While a hemoglobin count slightly below the normal range can cause mild symptoms, it's unlikely to have a fatal outcome. Hemoglobin levels have to be severely low to be life-threatening. According to the NIH, a hemoglobin level below 6.5 g/dL is life-threatening and can cause death.²
The signs and symptoms of low hemoglobin may overlap with symptoms caused by many other medical problems. If you are experiencing symptoms of low hemoglobin, it's imperative that you see a doctor to determine the true cause.
Your healthcare provider will order a blood test called a complete blood count (CBC) to help diagnose and then treat low hemoglobin. You're also likely to undergo a physical exam and other diagnostic tests.
Doctors treat low hemoglobin by identifying the underlying cause. For instance, if you have a lower-than-normal hemoglobin count, your healthcare provider may order a test that reveals iron deficiency anemia.
The doctor will treat your anemia with iron supplements and advise you to make dietary changes. In some cases, iron infusion (when the iron is delivered through periodic injections) is recommended. Additionally, if your low hemoglobin is a result of gastrointestinal bleeding, your healthcare provider may perform surgery that stops the bleeding.
In most low hemoglobin cases, addressing these underlying causes will restore normal hemoglobin or red blood cell count. Patients with dangerously low hemoglobin levels (below 7 g/dL) may require transfusion using packed red blood cells (PRBC) to restore normal hemoglobin levels.
Low hemoglobin can't always be prevented. However, some lifestyle modifications can help boost your hemoglobin levels. Dietary changes, such as increasing the consumption of foods high in iron and folate, can increase the production of red blood cells and, consequently, hemoglobin.
You can increase iron in your diet by eating more leafy greens, red meat, liver and organ meats, beans and lentils, baked potatoes, and fortified cereals. Foods that are high in folate include lettuce, avocado, kidney beans, rice, and peanuts.
Hemoglobin is a compound in red blood cells (RBCs). It's responsible for carrying oxygen from your lungs to all the cells in your body. The hemoglobin level in red blood cells fluctuates and can go below the healthy range.
There are many possible causes for low hemoglobin, from diseases such as anemia, cancer, and genetic blood disorders to blood loss and a diet low in iron. Regardless of the cause, a lower-than-normal hemoglobin level (anemia) can have adverse effects on your health.
A low hemoglobin level often causes noticeable symptoms, including fatigue, pale skin, trouble breathing, rapid heart rate, and, as the condition worsens, heart problems and even death. Hemoglobin levels have to be extremely low (below 6.5 g/dL) to cause death.
Fortunately, low hemoglobin is reversible. A doctor can restore normal hemoglobin levels by diagnosing and treating the underlying problems. From diet to surgery and blood transfusion, there are various methods of increasing hemoglobin levels depending on the underlying cause.
Anaemia | World Health Organization
Iron-deficiency anemia | NIH: National Heart, Lung, and Blood Instititute
Anemia in chronic kidney disease | National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)