The number of white blood cells in the blood, indicating immune system activity and infection-fighting capacity.
FULL EXPLANATION
White blood cells (leukocytes) are the cells of the immune system that protect the body against infection and foreign invaders. The total WBC count includes several types: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Elevated WBC can indicate infection, inflammation, stress, or certain conditions. Low WBC (leukopenia) may indicate immune suppression. The differential (breakdown by type) provides more specific diagnostic information.
WHY IT MATTERS
WBC count is a basic but important marker of immune function and can indicate infection, inflammation, or other health issues requiring attention.
HOW TO IMPROVE
Maintain healthy WBC through adequate sleep, regular moderate exercise, stress management, good nutrition, and avoiding excessive alcohol or smoking.
NORMAL RANGES
Normal WBC: 4,500-11,000 cells/mcL. Elevated (leukocytosis): >11,000. Low (leukopenia): <4,500. Athletes may have lower baseline counts.
RELATED TERMS
Cytokines
Signaling proteins released by cells that regulate immunity, inflammation, and cell communication throughout the body.
C-Reactive Protein
A blood protein produced by the liver that increases in response to inflammation, used as a marker of systemic inflammation.
Overtraining Syndrome
A condition of decreased performance and fatigue that occurs when training exceeds recovery capacity for an extended period.
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