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Blood Simple

CBC and Other Tests for Health, Fitness and Peace of Mind

Tests of blood and liver functions are no less important than any of the other tests we've talked about in this series. Knowing the status of your blood cells, for example, gives you a clear indication of your oxygen-delivery system. Optimal oxygen in body tissues translates into maximum workout energy and efficiency.

Knowing the condition of your white blood cells gives you a status report on your immune system. Unless your immune system is functioning at a high level, you'll be subject to any disease-causing organism you're exposed to, including the sundry bacteria and viruses that are ubiquitous in everyday life.

Having an optimal immune system also helps protect against the onset of such diseases as cancer. The older you get, the weaker your immune defenses get, and the greater your chances of acquiring some type of cancer. Certain lifestyle habits are also known to dampen immune response, regardless of age'poor nutritional habits, overtraining, smoking and not getting sufficient rest and sleep.

How the Immune Cells Function

Blood cells are produced in bone marrow through a process called hematopoiesis. Red blood cell production is regulated by a hormone synthesized in the kidneys called erythropoietin (EPO). Anabolic steroids increase the kidneys' production of erythropoietin and were formerly used to treat certain kinds of anemia. The use of steroids for that purpose has been superseded by recombinant DNA or artificially produced EPO. When oxygen levels in the blood decline, EPO stimulates the bone marrow to produce more red blood cells (RBCs). Athletes have taken advantage of that by using EPO drugs as a means of blood doping. EPO reliably increases RBC numbers, which equals greater oxygen delivery to muscles and less muscle fatigue. Its effect is similar to that of old-style blood doping, which involved withdrawing blood from an athlete that was later reinfused before a major athletic event, thereby packing the blood with a surfeit of RBCs. Unfortunately, it could also result in an excess number of blood cells, leading to a pathological blood thickening that not only reduced blood flow but also increased the risks of internal clotting and stroke.

Red blood cells include a protein called hemoglobin that carries oxygen to body tissues. Hemoglobin production is affected by various nutrients, as is that of RBCs themselves. The nutrients include iron, vitamins B6 and B12, folic acid, copper and others. RBCs normally live for 120 days before being broken down in the liver.

White blood cells (WBCs) have a far shorter existence than RBCs. Although much larger than RBCs, white blood cells are outnumbered by RBCs by about 1,000 to 1. WBC numbers, however, can double within hours, since they're the true soldiers of our immune defense. They can be called to action against various types of noxious invaders, such as tissue trauma, injury and inflammation. In fact, WBCs participate in the inflammatory process that occurs in muscle following an intense training session, drawn to the area by cytokines, or chemicals, released by damaged tissue.

The various WBC types include the following:

'Polymorphonuclear neutrophils. Also known as 'polys,' they're the first line of defense against bacterial invasion and work through phagocytosis, a process that engulfs foreign agents in the body and removes them. Once activated, they cruise the blood for about six hours, and when they've absorbed bacteria and other debris, they die and become the main component of pus.

'Monocytes. These are the largest of the blood cells and work to remove injured and dead cells. When released from bone marrow, monocytes are still immature. They mature only after they enter tissue, when they convert into macrophages. Having increased monocytes in the blood is a good indication that the recovery process is going well.

'Eosinophils. Found in the skin and lungs, they're involved mainly in inflammatory and allergic reactions. Some scientists think that these particular WBCs were the primary defense against worm infestation in ancient man.

'Basophils. Also called mast cells, they release heparin and histamine and are thus the major effector of symptoms evident during allergic reactions. The heparin released from basophils decreases blood clotting, thus enabling other WBCs to more easily circulate to damaged tissues.

'Lymphocytes. These WBCs fight bacterial and viral onslaughts. They come in two types: B and T cells. T cells are so called because they develop in the thymus gland, located in the center of the chest. B cells develop in the bone marrow. T cells are subdivided into various other types, such as killer T cells, which are particularly active against tumors and viruses; and suppressor and helper T cells, the latter being a target of the HIV virus. ALL The CBC Tests

Here are the various complete blood count (CBC) tests and what they mean:

'Reticulocyte count. Reticulocytes are immature red blood cells. In men the normal lab value for them is 0.5 to 1.5 percent of total erythrocytes (red blood cells). The value is higher during infections, liver cirrhosis, folic acid deficiency (folic acid is required for RBCs to mature) and bone-marrow failure. The number is also elevated in anemia.

'Hemoglobin. The hemoglobin level indicates the oxygen-carrying capacity of the blood. The normal value for men is 14 to 18 grams per deciliter of blood; for women, 12 to 16. Hemoglobin levels drop during iron-deficiency anemia or overhydration. A higher-than-normal level may point to polycythemia, or an excessive number of red blood cells, as may occur with use of EPO drugs or blood-doping procedures. Higher levels of hemoglobin also may indicate dehydration or shock, or they may be an adaptive response to living or training at higher altitudes that is characterized by lower oxygen levels. In that case the body compensates by producing more EPO, which leads to higher numbers of RBCs and, consequently, higher hemoglobin levels.

'Hematocrit. This test shows the RBC concentration and is an indicator of the viscosity, or thickness, of the blood. The normal level in men is 40 to 52 percent; in women, 38 to 47 percent. The factors that increase hemoglobin also increase hematocrit, and having too thick a blood level not only interferes with oxygen delivery but greatly increases the chances of having a stroke as well. The slower the blood circulation, the greater the odds that blood clots may occlude an artery in the brain, resulting in a stroke.

'Mean corpuscular volume (MCV). This test is an indicator of the size of RBCs. The size of the cells points to possible types of anemia. Normal value is 80 to 90 microns in men; in women, 82 to 98.

'Mean corpuscular hemoglobin concentration (MCHC). This measures the average level of hemoglobin in a single red blood cell. Normal values are 32 to 36 percent. Again, abnormal results point to anemia.

'Mean corpuscular hemoglobin (MCH). This shows the average weight of hemoglobin and is calculated by dividing total hemoglobin by total RBC count. Normal is 27 to 31 picomoles per RBC; an abnormal level is an indicator of anemia.

' White blood cell count. This measures the number of leukocytes in one cubic milliliter of blood. Normal is 5,000 to 10,000. When low, the count points to viral infections, bacterial infection and toxic reactions to various heavy metals. When high, it could also point to other types of bacterial infections and leukemia, a cancer of the blood. Tissue injuries, such as burns, heart attacks and others, also increase WBC counts. The greater the increase in WBC, the greater the intensity of infection.

'WBC differential: neutrophil count. This measures neutrophils in the blood. The value is low during infections and with the use of certain drugs. The value increases with other types of infection, such as herpes or gonorrhea. Taking too high a dose of thyroid drugs can also increase the neutrophil count.

'WBC differential: eosinophil count. This measures the WBCs specific to allergies. Low levels are found in postsurgical patients, and they're related to increased blood insulin levels, ACTH from the pituitary gland and mental distress. High levels occur during any type of allergy-related disease, such as asthma, hay fever or food or drug sensitivity. Overtraining also leads to elevated eosinophil counts.

'Basophil count. Measures WBCs that easily stain with dyes. Low levels occur during stress, hyperthyroidism and during ovulation and pregnancy; higher levels occur with cancer and anemia.

'Monocyte count. Low counts of monocytes are rare. High levels point to various types of infection, including hepatitis, and some types of autoimmune diseases.

'Lymphocyte count. Low levels point to stress from burns or tissue trauma, increased cortisol levels and HIV infection. High levels also point to infections, including mumps, influenza and infectious mononucleosis. The count is also high in cases of leukemia and excess thyroid release. Testing for Other Compounds

The usual blood tests also measure various electrolytes or minerals in the blood. Potassium is usually kept within a tight range, since too much or too little can disturb heart rhythm. Some competitive bodybuilders have run into problems with elevated potassium levels after taking both a potassium-sparing diuretic, such as Aldactone, and supplemental potassium at the same time. The drug retains potassium in the body, thereby bringing the mineral to a potentially toxic level. Normally, the kidneys rapidly excrete excess potassium.

Other diuretic drugs promote the excretion of both sodium and potassium, leading to such symptoms as severe muscle cramps during posing. Taking insulin can also lower blood potassium, because insulin pushes potassium out of the blood and into cells. Other symptoms of low blood potassium include weakness, confusion, abdominal distension, nausea and heart arrhythmia.

Elevated blood potassium is unlikely to occur unless potassium-sparing drugs are used with concentrated-potassium supplements or when the kidneys aren't functioning properly. Crash injuries and burns also result in elevated potassium levels, as injured tissues release the mineral into the blood. Signs of elevated blood potassium include irritability, nausea, vomiting, diarrhea, confusion, cramping, muscle weakness, slurred speech and heart rhythm disturbances.

Blood sodium levels can drop during vomiting, excessive sweating, diarrhea and purposely decreased sodium intake. Aware that sodium promotes water retention, bodybuilders often decrease their intake of sodium to nearly zero. But the body requires a minimum of about 220 milligrams of sodium a day. Otherwise, side effects similar to those typical of potassium deficiency, such as muscle cramping, show up. When sodium levels drop too low, coma and even death can result.

Chloride usually combines with sodium to form a salt. Common table salt is sodium chloride. Although overshadowed by sodium, chloride has its own important attributes. In the stomach, chloride combines with hydrogen ions to form hydrochloric acid, which is required for the initial stage of protein assimilation and for mineral uptake. Chloride also helps maintain the blood's vital acid/base balance, a feature it shares with other minerals, such as potassium. When sodium is low, blood tests usually show low chloride levels too.

Carbon dioxide also reflects acid/base status, as well as the bicarbonate level of blood. Bicarb is the major buffer the blood needs to counter elevated acidity. Elevated levels of CO2 point to blood alkalosis (excess alkalinity), while elevated levels indicate acidosis. Abnormal levels usually call for an arterial blood gas test to determine the cause of the problem.

Glucose levels depend on when you last ate before the test. For best results don't eat for at least 12 hours before it. Elevated levels may mean diabetes, while low levels result from usage of insulin or other hypoglycemic drugs.

Of the common kidney blood tests, BUN and creatinine are part of the usual blood workup. BUN stands for blood urea nitrogen and reflects the liver's manufacture of urea, a protein metabolic waste product excreted through the kidneys. When the kidneys aren't functioning properly, they become less efficient at excreting urea, causing a rise in BUN levels. On the other hand, simply eating more protein than usual'a common practice among bodybuilders and other athletes'can also lead to an elevation of BUN. BUN also increases when you're dehydrated; for example when you aren't taking in enough fluids.

Serum creatinine is a more specific index of kidney function than BUN. Creatinine is the major metabolic waste product of creatine and is produced at a constant rate dependent on skeletal muscle mass. Most doctors are alarmed when they view high blood creatinine, which often means kidney problems. Taking megadoses of supplemental creatine, such as during a creatine loading phase, may also temporarily increase blood creatinine values. So it's prudent to tell your doctor that you're on creatine food supplements before you undergo a blood test that measures creatinine. Some hapless bodybuilders have neglected to do so, leading their doctors to suspect impending kidney failure.

Finally, a word about liver tests. Nearly anyone who regularly lifts weights will show a minor elevation of a liver enzyme called ALT, or SGPT. Found in muscle as well as the liver, the enzyme is released into the blood when muscle tissue is damaged, including by weight training. When blood tests show it to be slightly elevated, many doctors suspect liver problems unless they know about the weight training.

Don't neglect the importance of having blood tests at every major physical checkup'at minimum once or twice a year and more often if you suspect problems or go on an anabolic-drug regime. And you should demand to see the actual test results. Don't let your health provider patronize you by saying, 'Everything is normal,' which tells you nothing. The tests are your window into what's really happening in your body and can reveal problems that may not be apparent. Even more important, knowing how you stand can alert you to future problems that you can head off now. IM

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