What is low hemoglobin?

Hemoglobin (abbreviated Hb or Hgb) is a protein found in red blood cells. Red blood cells carry oxygen from your lungs to all the other organs in your body.
A low hemoglobin count means that the amount of hemoglobin in each deciliter of blood is less than 13.5 grams for men or 12 grams for women. Low hemoglobin values for children depend on their age.
A hemoglobin count that is a little bit lower than normal is typical for some people and may not indicate a problem. However, a hemoglobin count that is significantly lower than normal may mean that you have anemia, especially if you’re experiencing symptoms.
Symptoms of low hemoglobin
When you have anemia, either your body doesn’t have enough red blood cells or your red blood cells are not functioning well. If your red blood cells can’t get enough oxygen to the rest of your body, you may have symptoms such as:
Fatigue
Even with mild anemia, you may feel very tired and weak. Fatigue is often one of the first symptoms of anemia.
Pale skin and gums
Another early symptom of anemia is skin and gums that are paler than usual or yellowish.
Temperature issues
As anemia worsens, it can cause increased sweating or cold hands and feet.
Dizziness
Moderate anemia can make you feel dizzy (like the room is spinning) or lightheaded (like you might pass out).
Rapid heart rate
Fewer red blood cells mean your heart has to pump harder than usual to get enough oxygen to all the parts of your body, so your pulse may be faster. Severe anemia can even cause an irregular heartbeat.
Tinnitus
Someone with tinnitus hears sounds in their ears even when it is silent. When your heart has to work harder to get blood to your brain, you may hear the increased blood flow through your inner ear. Tinnitus is often described as “ringing in the ears,” but people with anemia may hear more of a pounding or whooshing sound.
Headache
Moderate to severe anemia can cause frequent headaches. Like the other symptoms listed here, headaches have other causes and don’t necessarily mean you have anemia.
Shortness of breath
Moderate anemia can make you breathe faster than normal. When anemia becomes severe, you may feel like you can’t catch your breath or experience chest pain.
Causes of low hemoglobin
There are dozens of issues that can cause anemia, ranging from infection to cancer. Some of the more common ones include:
Poor diet
Your body needs iron, protein, vitamin B12, folate (vitamin B9), and other vitamins and minerals to make red blood cells. If you don’t get enough of these nutrients from the food you eat, you may end up with too few red blood cells.
Pregnancy
During pregnancy, your blood volume increases, so you need more iron than usual. Your body also needs extra iron to support your baby’s growth and development.
Blood loss
When you lose blood, your body loses lots of red blood cells and iron. Reasons for blood loss include:
- Frequent nosebleeds
- Heavy menstrual periods (menorrhagia)
- Problems in the digestive tract (esophagus, stomach, intestines, etc.)
Tests for low hemoglobin
If you have some of the signs and symptoms listed above, call your doctor for an appointment. Your doctor may draw blood for a complete blood count (CBC) test. This test provides your hemoglobin count, the number of red blood cells in your blood sample, and other information helpful in diagnosing anemia.
Some people find out their hemoglobin is low when they try to donate blood. If your hemoglobin is only a little lower than the level required for donation, you may be able to wait and try again in a month or two. If your hemoglobin is low again or if you begin to have some of the symptoms above, make an appointment to see your doctor.
Treatment for low hemoglobin
The type of treatment will depend on the reason you have anemia. If your anemia is the result of low iron or a vitamin deficiency, you may need to change your diet or take supplements. This is by far the most common cause of and treatment for anemia.
More rarely, your doctor may diagnose and treat another underlying cause, such as ulcers.

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