Exercise generally boosts your immune system and white blood cell count. A low white blood cell count in athletes is common, but it may also indicate a more serious medical condition.
Normal White Blood Cell Count
White blood cells, or leukocytes, make up about 1 percent of your blood and are also found in your lymph tissues. These are the cells that fight off infections and illness. Your doctor may order a blood test to check your white blood cell count if you are ill or as a part of a regular check-up or health screening. A normal range for adults is 5,000 to 10,000 per cubic millimeter.
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You have five types of white blood cells in your system:
- Basophils are the cells that help control the immune response and notify other cells when an infection is found.
- Neutrophils kill bacterial and fungal infections in your body.
- Lymphocytes create antibodies that work against bacterial and viral infections.
- Monocytes live longer than other white blood cells and work to break down bacteria in your system.
- Eosinophils attack other types of infections such as parasites and cancer. They are also active during an allergic response.
The University of Rochester Medical Center notes that your white blood cell count may be outside of this normal range for many reasons.
An elevated white blood cell count is often a sign that your body is fighting off an infection. It may also be a symptom of certain medical conditions such as myelodysplastic syndrome or myeloproliferative disorder, both of which cause abnormal production of blood cells.
A low white blood cell count is also a cause for concern. It may be a sign of a serious illness, such as cancer, HIV or AIDS. Cancer treatments also lower the number of blood cells in your system.
If your results reveal an abnormal white blood cell count, your doctor may order additional tests to find the source of the infection or disease. Some of these tests may include:
- CBC, or complete blood count, which measures all components
- Differential white blood cell count, which measures each type of white blood cell
- Neutrophil test, which specifically looks for a low neutrophil count
- Bacterial and viral cultures to detect specific infections in your system
- Biopsy to check for blood cancers
- Imaging tests to further search for infections
Weight Lifting and WBC Count
Exercise, including weight lifting, will typically increase your total white blood cell count. This is one reason why physical activity good for your health and your immune system.
In a six-year study conducted on healthy young adults and published in the February 2013 edition of the World Journal of Experimental Medicine, researchers have found that white blood cell types consistently increased after five minutes of intense exercise. One group exercised by running or skiing for one hour and then rested for three hours. In this group, an increase in neutrophils and eosinophils, as well as a slight increase in lymphocytes, was observed.
The change in white blood cells count in this study was similar in all groups, whether the individuals cycled or ran, suggesting that the type of exercise that you do may not matter. Physical activity in all its forms can boost your immune system. The subjects' fitness level also did not seem to affect the results.
Read more: Normal WBC Range in Children
When Exercise Lowers WBC Count
While most types of exercise boost your white blood cell count, in some cases, a low white blood cell count in athletes, especially endurance athletes, may occur. This condition is usually a cause for concern, but in an endurance athlete, a depressed immune system may be a side effect of intense and prolonged exercise and not an underlying health condition.
In a 10-year study published in the July 2010 online publication of the European Journal of Applied Psychology, researchers have assessed the effect that different sports had on an athlete's white blood cell count. Neutrophinia, or a low neutrophil count, was most commonly observed in endurance athletes, specifically 17 percent of athletes participating in cycling and 16 percent of those participating in triathlons.
The study confirms that endurance athletes tend to have lower neutrophil and total white blood cell levels that other athletes. This can pose a health challenge because decreased neutrophil levels can significantly increase your chances of contracting a bacterial infection. The study excluded individuals who were not healthy, so the effect that the decreased cell count has is unclear.
Further research is required to determine the reasons that neutrophil and total white blood cell count decreases in some athletes. Theories suggested by researchers include:
- Faster cell death
- Decreased production of neutrophils in the bone marrow
- The cells migrating out of the bloodstream and into the tissues at an increased rate
- The increase in plasma volume seen in endurance athletes
Overall, these findings indicate that the low white blood cell count in athletes may be a normal adaptive response to intense activities.
In a more recent study published in the August 2017 edition of Frontiers in Physiology, researchers found similar results in a study of a small group of elite athletes during a competition season. By the end of the season, researches noticed significant decreases in the levels of white blood cells, neutrophils and monocytes, as well as a decrease in mean platelet volume.
In many cases, individuals with leukopenia, or a low white blood cell count, don't experience any symptoms, notes Temple Health. However, this condition does put you at risk of developing a serious infection. Contact your doctor if you have a fever, chills and sweating and take precautions to avoid infection.
Other Potential Causes
Unless you are exercising for extended lengths of time at an intense level, a low white blood cell count may be a sign of a more serious underlying condition. Disorders and diseases that affect blood cell production in the bone marrow are one possible cause.
For example, if an individual has aplastic anemia, the bone marrow cells used to make blood cells are damaged, causing blood cells to be produced at a lower rate, notes the National Institute of Diabetes and Digestive and Kidney Diseases.
Myelodysplastic syndromes may also lower white blood cell count. Although blood cell production continues at a normal rate with this condition, the cells are damaged and abnormal and often die before reaching the bloodstream. Those that do reach the bloodstream are unable to effectively fight infections.
These conditions may be caused by chemotherapy, high levels of ionizing radiation from X-rays or a radiation plant, toxic chemicals including benzene and certain viral infections. Symptoms may include fatigue, frequent infections, pale skin, red spots on the skin, excessive bleeding and bruising.
Treatment options include blood and bone marrow transplants, blood transfusions and medication. The first treatment option for myelodysplastic syndrome is often supportive care to manage the symptoms of the disease.
Some viral infections, including HIV and AIDS, may also lower the body's white blood cell count. HIV, or human immunodeficiency virus, attacks the immune system, resulting in a low white blood cell count. Individuals with a weak immune system are more likely to contract infections and may have a hard time fighting pathogens.
The disease is transmitted through bodily fluids, including vaginal fluid, semen and breast milk. While there is no cure, antiretroviral therapy may slow the progression of the disease.
AIDS, or acquired immunodeficiency syndrome, is the late stage of an HIV infection when the immune system is extremely damaged and the white blood cell count, specifically CD4 cells, a type of lymphocyte is extremely low. At this stage, individuals are especially likely to get an opportunistic infection.
Certain cancers, such as lymphoma and leukemia, can also affect the bone marrow and blood cell production, causing a low white blood cell count. Cancer treatments, including radiation therapy and chemotherapy, may also cause white blood cell levels to drop too.
Some medications may also lower your white blood cell count. Immunosuppressant drugs, histamine-2 blockers, anticonvulsants, antithyroid drugs and clozapine are just a few to mention.
Precautions to Avoid Infection
Having a low white blood cell count affects your body's ability to recognize and respond to infections and increases the likelihood that you may become seriously ill. Wexner Medical Center recommends you take precautions to keep healthy while following the treatment plan provided by your doctor.
Wash your hands frequently using antibacterial soap and dry them with a disposable paper towel. If you use a cloth towel, change it at least once a day for a clean one. Shower daily and keep your nails trimmed and clean. Brush your teeth with a soft brush. Shave using an electric razor to avoid nicks and cuts. Apply lotion to protect your skin from drying and cracking.
While some exercise may help increase your white blood cell count, consider working out at home to avoid exposure to potential infections at the gym. Take precautions if you are participating in activities where you may be cut. For example, if you are gardening, remember to wear gloves.
If your white blood cell count is extremely low, your doctor may recommend wearing an N-95 face mask when out in public or when in a dusty or dirty room. You may also need to take your temperature twice per day to monitor for an infection or fever.
If you notice any new signs of infection, contact your doctor immediately. Some things to look out for include:
- Rashes, redness or swelling on the skin
- Cuts that don't heal within three days
- White patches, bumps or redness in the mouth
- Watery diarrhea
- Fever greater than 100.4 degrees Fahrenheit
- University of Rochester Medical Center: "What Are White Blood Cells?"
- University of Rochester Medical Center: "White Cell Count"
- Ohio State University Wexner Medical Center: "Low White Blood Cell Count Precautions"
- World Journal of Experimental Medicine: "Effects of Exercise on Leukocytosis and Blood Hemostasis in 800 Healthy Young Females and Males"
- European Journal of Applied Psychology: "Lower White Blood Cell Counts in Elite Athletes Training for Highly Aerobic Sports"
- Frontiers in Physiology: "Enhanced Strength and Sprint Levels, and Changes in Blood Parameters During a Complete Athletics Season in 800 m High-Level Athletes"
- National Institute of Diabetes and Digestive and Kidney Diseases: "Aplastic Anemia & Myelodysplastic Syndromes"
- HIV.gov: "What Is HIV?"
- Temple Health: "Leukopenia"
- U.S. National Library of Medicine: "WBC Count"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.