So last I left off I was talking about how the increase in red blood cell count would increase the potential amount of oxygen your blood can carry at a given time, would this increase VO2Max? Theoretically it should right? Noah provided a good short reading from JAP in the comments of the last post on the trainability of VO2Max, maybe a good post for next semester when I'm taking the 2P09 physiology class.
The importance of red blood cell count is pretty easy to understand, a red blood cell has a pigment called hemoglobin that has a heme (iron) component responsible for the red coloration of the blood as well as the color of what we excrete after it's broken down and a globin (protein with 4 polypeptides) component. The oxygen binds to the iron component and the amino acids of the polypeptide component bind CO2 to be carried away from the tissues and out by way of the lungs. There are 4 heme components per red blood cell and each one can carry one molecule of oxygen, when oxygen is bound to hemoglobin it becomes an oxyhemoglobin. The reason that carbon MONOxide poisoning is so dangerous is because the iron of the hemoglobin has a higher affinity to carbon monoxide than it does to oxygen, the hemoglobin will pick up carbon monoxide and it will take up one of the 4 spots it would have for oxygen. The more carbon monoxide that a red blood cell picks up, the less oxygen it can carry, you're slowly suffocating yourself.
So, more red blood cells means more oxygen can be carried in the blood at a given time, which means more fuel for the working muscles and because road and mountain bike racing require big aerobic efforts and use up quite large quantities of fuel, the more oxygen they have at their disposal the better. How can we get more of those little red things? A red blood cell is also called an erythrocyte and the production of erythrocytes is called erythropoiesis. There are cells in the red bone marrow with receptors for a certain hormone, when this hormone reaches those receptors it stimulates the cells to transform, multiply, and synthesize reticulocytes secreted into the blood and eventually (1-2days) it loses its remaining polyribosomes and becomes a mature erythrocyte. It would make sense that the hormone would be called erythropoietin (EPO), it's secreted by the kidneys and liver when it sense a state of hypoxemia; a deficiency of oxygen in the blood stream. The reason for the lack of oxygen could be from a number of things, but when you're exercising hard and blood can no longer keep up with the large oxygen demand of the tissues they enter a state of oxygen deficiency called hypoxia. When there is less oxygen in the air (lower partial pressure), such as at a higher altitude, the kidneys are already sensing a state of hypoxemia even before training begins and the body adapts by increasing hematocrit, or red blood cell count, to accommodate the needs of the body's tissues.
As you all know, for some, EPO doesn't come solely from the kidneys and liver, you can call these people blood dopers, although they aren't the only kind. Everyone has heard the famous quote from Dr. Ferrari that "EPO is as safe as orange juice", well not that I'm pro-doping in any way whatsoever but from a physiological point of view he's right. EPO will increase hematocrit, or how much of the blood do erythrocytes make up, and therefore make the blood thicker and harder to pump, but unlike the lungs, the heart is trainable and can overcome this disadvantage. The heart is trainable because it consists of a thick layer of myocardium, or muscle of the heart, that can increase the strength of each contraction, the ventricles stretch more each time they dilate and the more they stretch the stronger the contraction because it has more blood to eject. An endurance athlete should have a low resting heart rate because, at rest, the heart can supply the body's needs in fewer beats in one minute than it could if it wasn't trained. Also, drinking more water will make the blood thinner. Although EPO is safe, it's not like you can take as much as you want without any bad effects because too much of anything, even orange juice, can have negative effects.
Orally ingesting EPO isn't the only way to raise hematocrit, when you're testing to see someone's hematocrit you have to remove a sample of blood and spin it in a centrifuge. Once the plasma has been separated from the formed elements you can remove the formed elements and re-inject them into the blood stream. Another very popular method of blood doping is to have a training camp for an extended period of time at high altitude and the "athletes" will get many tests done to keep checking their red blood cell count, the higher the count the better the blood. However, they also have to make sure that the level does not exceed the legal limit set by the UCI which is 50%, on average a person's hematocrit will be roughly 45%. This isn't a relatively large increase but a 5% gain makes a HUGE difference when it comes to endurance training and racing. Once the team "doctors" are satisfied with the number, they remove the blood and store it at the proper temperature, those clear bags in the fridge contain red liquid gold when you're 14 days into the Tour and every energy source in your body is being depleted as you speak. A fresh bag of quality blood is more than the body could ever ask for.
So, maybe after reading this you feel like doping, if that's the case then I'm very sorry but you were a cheater at heart anyways so I take that back because I'm not very sorry at all. Either way, having proper knowledge on blood doping and knowing exactly how to do it is one thing, the equipment involved is expensive as hell, it's very time consuming, it has to be done properly each and every time with absolutely no error in execution. Think about a screw up like giving person x's blood that is type A to person y who has type B blood, yeah, not good. BUT I can tell you that proper nutrition can help to increase red blood cell production; of course there's iron seeing as it's the reason the blood is red so must be kind of important, also, vitamin D and folic acid promote rapid cell division and DNA synthesis and there's vitamin C and copper that are cofactors for some enzymes that synthesize hemoglobin.
SOURCES: PEKN 1P90 course notes & Physiology and Anatomy 5th Edition by K.S. Saladin
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