In this article

What Does a Low White Blood Cell Count Mean?

Low white blood cell count (leukopenia) signals an issue with the immune system's ability to ward off infections. Explore the science behins this condition.

Ashley Reaver
By Ashley Reaver
Jovan Mijailovic
Edited by Jovan Mijailovic

Updated June 11, 2024.

a woman sitting in a chair wearing a face mask

White blood cells (WBC) are the driving force behind a healthy immune system. Yet, a low count in these combatant cells sometimes spells trouble. Understanding their levels is best done by comparing recent results with your historical blood test data.

Here's a comprehensive overview of white blood cells, the reasons they might be low, and how to support their production. Explore reasons behind fluctuations in their numbers and learn tips to keep your immune defense strong.

» Unlock personalized insights to optimize your health using a data-driven approach to wellness

What are white blood cells?

White blood cells, or leukocytes, are the body’s primary defense against infection. They are primarily produced in the bone marrow, although the spleen plays a role in the production, too. [1]

Our system creates WBCs in response to an infection, circulating them throughout the blood and lymph systems. Their total count in a test is the sum of five different types—all with different roles:

  • Neutrophils
  • Eosinophils
  • Basophils
  • Lymphocyte
  • Monocytes
a blood test tube with blood and blood cells

Neutrophils: The immune system's first responders

Within minutes of an injury, trauma, or tissue inflammation, neutrophils arrive at the scene. They control the traffic going to and from the infection site by recruiting additional WBCs specialized to the type of invader.

They also engulf the pathogen and dissolve it, living up. You might've even seen the process, as they're the basis of pus. The lifespan of a neutrophil is very short, ranging from five hours to a few days.

What is the normal range for WBC count?

Neutrophils make up 60–70% of your total WBC count. That's why a deficiency in them is called neutropenia. There isn't a single definition of what's "normal" when it comes to your levels; it usually depends on the lab where you went for a blood test.

» Decipher your blood test results before your next doctor's visit

Usually, clinicians consider 4,000-11,000/microliter of blood a normal WBC count. They usually write it as 4.0-11.0 thousand/μL. If they analyze your neutrophils, too, a standard range would be 1500-7800 cells/ μL. You may also see this value as a percentage of your total WBCs.

Considerations for low white blood cell count

Low white blood cell counts make you vulnerable to diseases, helping them last longer and cause more harm. Given that they vary daily and hourly, a blood test won't give you a definitive conclusion about your immune health.

» Learn everything there is to know about a high white blood cell count

A single data point won't help you pinpoint the cause. You should collect and compare recent blood results with past ones to identify a pattern or deviation from ranges that are regular for you.

You might've had a complete blood count (CBC) done as a routine test at your doctor's office or if you’ve ever been hospitalized. So, track down those papers and use them as a comparison point for your new results.

What if your "normal" is lower than the defined range?

A percentage of the population has a lower “resting state” level of WBC. You may have some genetic variations that don't necessarily predispose you to an increased risk of infection, like people of African, Middle Eastern, and some regions of European descent. [2,3]

» Find out how your DNA and lifestyle interact to influence your healthspan

If you have a history of WBC levels just below the lower threshold of 4.0 thousand/μL and haven’t been sick frequently throughout your life, you likely belong to the group of people mentioned above.

» Want to understand blood test results? Check out our guide on complete blood counts

Maybe you don't have such a history but are seeing a pattern lately. In such cases, your body may be fighting an infection. [4] If you feel well by the time you receive your results, your levels will likely normalize. A single low WBC count often indicates that your immune system is working as it should be.

Consistent counts below 3.5 thousand/μL, especially under 3.0 thousand/μL, may be concerning. That's why you should consult your healthcare provider.

The most common reasons for low WBC count

Reasons for a low WBC count range from those relatively benign to those more serious, with the most common being:

  • Vitamin and mineral deficiencies: Vitamin B12, folate, B6, copper, and zinc are vital for WBC production. Chronic malnutrition and alcoholism are some of the leading causes of these deficiencies. Consult a doctor before considering supplementation.
  • Viral infections: Tuberculosis, HIV, and hepatitis B and C lead to persistently low WBC levels, but you need more than a single test to identify them as the cause.
  • Autoimmune diseases: Some conditions, like rheumatoid arthritis, may cause the immune system to make more WBCs to attack healthy tissue in the body.
  • Bone marrow cancers: Most white blood cells come to be in the bone marrow, so cancers attacking it will cause extremely low WBC counts.
  • Treatment and medication: People undergoing chemo may develop low WBC count as a reaction to the procedure.

If you have a chronically low WBC count, wash your hands frequently, wear a face mask, and avoid sharp objects so you don't cut yourself. If you do, keep the wound clean.

6 ways to improve your white blood cell count

If your resting white blood cell count is low, lifestyle changes might not affect it. But for other factors like the ones above, specific actions can help lower the strain on your immune system and enhance protection against pathogens.

1. Manage your stress

Mental, emotional, and physical stress impact the body's ability to defend against infection. Allostatic load, the stress-induced wear on the body and brain, influenced by adrenalin and cortisol, can compromise immune response as the body adapts to stressors. [7]

» Chronic tension can weaken your immune system. Find out how stress may be causing low WBCs

2. Get adequate sleep

The impact of inadequate sleep on white blood cells is well documented. Sleeping 6-8 hours per night can help you maintain normal levels of white blood cells, predominantly neutrophils. [8]

» Something disrupting your REM phase? Discover expert tips to reclaim your sleep and finally feel rested

3. Engage in regular physical activity

Exercise affects WBC count and immune function in a U-shaped curve: both insufficient and excessive exercise raise infection risk. For example, frequent intense workouts during cold months in endurance sports like cycling and running may cause an upper respiratory infection, so we recommend adequate rest days to reduce the incidence. [5,6]

» Train smarter, not harder. Explore how low-intensity zone 2 workouts can boost your endurance and keep you exercising for years to come

Regular moderate-intensity exercise, like 30 minutes daily for five days a week, supports optimal white blood cell levels. [9, 10]

If you're feeling tired, low WBCs aren't the likely cause. But if it just so happens that the two overlap, both are likely symptoms of an underlying issue. This could be overtraining, autoimmune diseases, viral infections, cancers, and low folate and B12 levels,

» T levels low? You could be overtraining

4. Eat a variety of fruits and vegetables

Fruits and vegetables, rich in vitamins, minerals, antioxidants, and phytochemicals, support white blood cells and overall immune function. Essential antioxidants to focus on include vitamins A, C, E, and selenium.

  • Vitamin A is found in colorful fruits, vegetables, and dark leafy greens and is better absorbed with fat and varied preparation.
  • Vitamin C is found in citrus, berries, broccoli, bell peppers, kiwis, and Brussels sprouts, and it requires limited cooking to retain its content.
  • Vitamin E is mainly in nuts and seeds, with wheat germ and sunflower seeds being prime sources. Selenium's top source is Brazil nuts, which are two pieces daily that fulfill the recommended amount. [11,12]
the four different types of food are shown

5. Maintain a healthy body weight

Excess body weight is associated with elevated levels of white blood cells, as it can cause an increase in inflammation and result in a WBC imbalance. [13]

6. Stop smoking

Smoking causes your white blood cell count to be elevated, as it causes your body to be in a constant state of inflammation and damage caused by tobacco. [14]

» Eager to safeguard your immune system? Explore how inflammation affects heart health

Boost your WBC count, power your immunity

Maintaining a healthy white blood cell count is essential for a robust immune system and overall well-being. While temporary fluctuations in WBC levels are normal and often resolve on their own, persistently low counts can leave you vulnerable to infections and other health issues.

If you notice a consistent pattern, you need to consult with your healthcare provider to identify and address any underlying causes. Prioritizing your immune health through mindful lifestyle choices can fortify your body's natural protection against illnesses and promote overall vitality.

Disclaimer: InsideTracker doesn't diagnose or treat medical conditions. Consult your physician for any health concerns.

» Learn what actions you can take to impact low white blood cell count by uploading your results and developing your Action Plan.


  1. R. Sarode, “Formation of blood cells,” Merck Manual Consumer Version, Jan. 17, 2024. Available:
  2. D. R. Crosslin et al., “Genetic variants associated with the white blood cell count in 13,923 subjects in the eMERGE Network,” Human Genetics, vol. 131, no. 4, pp. 639–652, Oct. 2011, doi: 10.1007/s00439-011-1103-9. Available:
  3. D. Reich et al., “Reduced neutrophil count in people of African descent is due to a regulatory variant in the duffy antigen receptor for chemokines gene,” PLOS Genetics, vol. 5, no. 1, p. e1000360, Jan. 2009, doi: 10.1371/journal.pgen.1000360. Available:
  4. L. A. Boxer, “How to approach neutropenia.,” PubMed, vol. 2012, pp. 174–82, Jan. 2012, doi: 10.1182/asheducation-2012.1.174. Available:
  5. P. L. Horn, D. B. Pyne, W. G. Hopkins, and C. J. Barnes, “Lower white blood cell counts in elite athletes training for highly aerobic sports,” European Journal of Applied Physiology, vol. 110, no. 5, pp. 925–932, Jul. 2010, doi: 10.1007/s00421-010-1573-9. Available:
  6. “Upper respiratory tract infection in athletes: influence of lifestyle, type of sport, training effort, and immunostimulant intake,” PubMed, 2000. Available:
  7. “Stressed or stressed out: what is the difference?,” PubMed, Sep. 01, 2005. Available:
  8. N. M. Johannsen et al., “Effect of Different Doses of Aerobic Exercise on Total White Blood Cell (WBC) and WBC Subfraction Number in Postmenopausal Women: Results from DREW,” PloS One, vol. 7, no. 2, p. e31319, Feb. 2012, doi: 10.1371/journal.pone.0031319. Available:
  9. E. A. Willis, J. J. Shearer, C. E. Matthews, and J. N. Hofmann, “Association of physical activity and sedentary time with blood cell counts: National Health and Nutrition Survey 2003-2006,” PloS One, vol. 13, no. 9, p. e0204277, Sep. 2018, doi: 10.1371/journal.pone.0204277. Available:
  10. L. Gravina et al., “Influence of nutrient intake on antioxidant capacity, muscle damage and white blood cell count in female soccer players,” Journal of the International Society of Sports Nutrition, vol. 9, no. 1, Feb. 2012, doi: 10.1186/1550-2783-9-32. Available:
  11. J. A. Colacino, A. E. Arthur, K. K. Ferguson, and L. S. Rozek, “Dietary antioxidant and anti-inflammatory intake modifies the effect of cadmium exposure on markers of systemic inflammation and oxidative stress,” Environmental Research, vol. 131, pp. 6–12, May 2014, doi: 10.1016/j.envres.2014.02.003. Available:
  12. J. Vuong, Y. Qiu, M. La, G. Clarke, D. W. Swinkels, and G. Cembrowski, “Reference intervals of complete blood count constituents are highly correlated to waist circumference: Should obese patients have their own ‘normal values?,’” American Journal of Hematology, vol. 89, no. 7, pp. 671–677, Apr. 2014, doi: 10.1002/ajh.23713. Available:
  13. T. Higuchi, F. Omata, K. Tsuchihashi, K. Higashioka, R. Koyamada, and S. Okada, “Current cigarette smoking is a reversible cause of elevated white blood cell count: Cross-sectional and longitudinal studies,” Preventive Medicine Reports, vol. 4, pp. 417–422, Dec. 2016, doi: 10.1016/j.pmedr.2016.08.009. Available: