White blood cells or WBC serve as the body's main defense system. When a germ, infection or abnormal cell enters the body, white blood cells rush to the area and attack the intruder. If the foreign cell or infection fights back, the number of white blood cells increases dramatically in an attempt to overpower the enemy. Since low WBC counts significantly increase your risk of developing an infection, exercise that causes a WBC drop can be somewhat unhealthy.
Blood Circulation & Exercise
During exercise, blood rushes through the body at a much faster rate than normal. As blood moves, white blood cells, oxygen and nutrients pass through the walls of capillaries and into the interstitial fluid, which is tissue fluid. In the reverse direction, cell waste products pass through the capillary walls into the circulation.
White Blood Cell Decrease
Unfortunately, certain types of exercise don't allow for proper blood circulation through all the body's capillaries. Instead, blood flow is focused to only the muscles that specific exercise has worked. When this happens, blood flow to the remaining cell tissues and organs is reduced. These areas then become deficient in oxygen, nutrients and white blood cells. Low- or moderate-intensity exercise that requires the same type of movement over a long duration of time can cause improper blood circulation and low WBC counts. These exercises include jogging, running, elliptical exercise, cycling and swimming. Opt for a higher intensity interval training program to ensure proper blood circulation and healthy WBC counts.
White Blood Cell Increase
Whether your white blood cell counts drop or remain relatively the same during exercise, the long-term effects of exercise should result in an overall increase in WBC counts. In fact, a 2007 study that NineMSN conducted showed that white blood cell counts can increase just 24 hours after exercise. Although exercise may temporarily reduce blood flow to certain areas, the amount of overall blood circulation still increases during physical activity. Since blood carries white blood cells, a higher number of WBCs surge through the body during and after exercise.
In a healthy body, one microliter of blood should contain approximately 4,500 to 10,000 white blood cells. Although exercise and stress can affect your WBC count, a significant increase or decrease in WBC generally indicates a disease process occurring within your body. High WBC counts typically indicate that your body is fighting off some type of infection or disease. Low WBC counts, on the other hand, might indicate that your body is losing its battle against the intruder. Low white counts might also be related to chemotherapy treatment or the body's inability to produce white blood cells. If your WBC counts are significantly high or low, consult your physician to determine the exact cause of the differential.