It's not easy to understand the complex world of blood doping and the use of illegal performance-enhancing drugs. EPO, steroids, growth hormone...it's a confusing mishmash of scientific jargon--until now. Thanks to this informative article by Dr. Mac Larson, you'll sound like a pro when discussing the specifics of EPO and blood doping with your friends.

What is EPO?

It's a bioengineered recombinant DNA hormone that is an exact duplicate of the human hormone erythropoietin. EPO is the natural chemical messenger that tells your body and bone marrow make red corpuscles ("Give me more blood!"). The human DNA code for the production of EPO in human bodies is was identified and then combined with bacterial DNA (recombinant) so that the bacteria produce an exact copy of the human hormone. So when you are taking EPO you are getting exactly the same hormone that your own body produces. You have to take it by injection. Taken by mouth it will be digested and not absorbed in an active form. In the human body it is made in the seemingly unlikely location of the kidney. This, however, does make sense when you understand that the kidney is basically in charge of the blood.

What is EPO’s role in modern medicine?

It is used in conditions that are characterized by anemia. Kidney failure patients and patients on dialysis have kidneys that no longer work well enough to do their job of hormone production. They become very anemic and benefit from erythropoietin injections. Other patients who have gone through cancer treatments or just have failing bone marrows can also benefit. It’s been a very useful pharmaceutical.

How much does EPO cost?

The average wholesale price for the two brands sold here is $120 for 10,000 units. A two-week high dose course that produces a large jump in the hematocrit lasting for up to 3-4 weeks could cost $500. But there would be benefits at lower dosages and lower costs. It probably costs a lot less to produce than its wholesale price. This is due in large part to recouping huge development and FDA certification costs, but also due to charging what the market will bear. This is one factor that accounts for the price differences of medications purchased in Mexico that are identical to their US counterparts. I have not researched the price of EPO in Mexico but it is probable that it is available much more cheaply than here.

How do EPO use and blood loading differ?

Blood loading involves giving you extra blood by transfusion. It is almost always your own blood that was drawn and frozen at least 3-4 weeks earlier. Your body then has the opportunity to make more blood to bring itself back to its normal blood count and volume. When the frozen blood (usually two units) is transfused it gives you a temporarily elevated blood count and volume. It is also possible to receive a transfusion of someone else’s matched blood type. This would work as well, but carries greater risk.

What does it do for normal healthy athletes? Does it have any “legitimate “ role to play for athletes in training? Does it help performance in any specific areas?

This is the more complicated part, but knowing how EPO works can benefit your training even if you don’t ever use it.
First you have to know two things about how your blood (if you’re reading this you're probably an athlete) and that of a more sedentary person differs. You have more blood than the average couch potato but you’re also more anemic. How can this be? When you exercise regularly you sweat and you often become at least temporarily dehydrated. This tells your body to make more of the stuff that keeps your blood liquid-plasma proteins and plasma. Your body will also be stimulated by exercise to make more red blood cells, but the liquid plasma part will increase even faster than red blood cells. Runners will often develop a relative anemia with hematocrits under 42%. The hematocrit is a number that tells us what percentage of your blood is the oxygen carrying red blood cells. If you had a hundred ounces of blood in your body and your hematocrit was 42% it would indicate that you have 42 ounces of red blood cells and 58 ounces of a combination of white blood cells, blood (plasma) proteins, and water. The vast majority of your body’s oxygen is transported in your red blood cells by being chemically bound to hemoglobin (a small amount is dissolved in the liquid part of the blood).

When you increase your hematocrit with a drug like EPO, by blood loading, or by living at altitude it also tends to increase your total blood volume. You end up with more circulating blood in your body with a higher percentage of oxygen carrying red blood cells. If you had a runner ‘s low hematocrit of 40% and increased your hematocrit by 10% that would still keep you within the average range for hematocrits-only bringing you to 44%. But you would theoretically increase your oxygen transporting capacity by 10%. An athlete wouldn’t necessarily gain this entire amount because there are other limiting factors, but it does have the potential to significantly increase performance. Interestingly, in blood loading studies hematocrits may only increase by a couple of points, while with EPO use you can boost hematocrits by any number you want. This doesn’t necessarily mean that EPO use will increase your performance more than blood loading, but it is possible. Performance studies have largely been done with blood loading; Human Studies Committees are uncomfortable with the amount of hematocrit increase that the competitive athlete will risk. So we don’t even know what the potential performance increase is with aggressive EPO use. It could increase performance by 10%. There are also some advantages when going to altitude. Blood loading will not keep you from getting altitude sickness but if you do not get altitude sickness or once you have acclimated, it can help transport the less available oxygen to your working muscles.

There are some other important functions of hemoglobin. It helps transport carbon dioxide back from the muscles to the lungs where it is exhaled into the air. It is also very important in buffering acid production in the body. What does this mean and why is it important? The body is designed to live and function best at a certain acid –base balance or pH of 7.4. When the body gets out of acid-base balance nothing works as well- including the muscles! Exercising produces lactic acid in the body. Lactate is an important fuel for the muscles and is a normal substance in the body. It is only a problem when you exceed your anaerobic or lactate threshold and it starts to accumulate rapidly. This occurs when you are running so fast that you can’t get enough oxygen to produce all your energy. You borrow energy by “ going anaerobic” and producing lactate. Carbon dioxide also forms carbonic acid as it is produced and dissolved in the blood. Hemoglobin helps buffer or lessen the change in the body’s acid-base balance that this carbonic and lactic acid produces. Two different people can produce the same amount of lactic acid during exercise but the one with more red blood cells and more hemoglobin handles it better-doesn’t “rig” or tie up as easily or as soon. In an aerobic event like the marathon, with the good marathoners running at their anaerobic threshholds, a higher hematocrit would allow them to throw in tougher surges because they would tolerate more lactic acid buildup. In a more anaerobic event like the 400 the buffering could keep you from tying up in the last straightway.
Increasing your hematocrit and total blood volume has some advantages (and dangers!) for hot weather races. When you exercise in hot weather your body demands more blood flow to your skin for cooling purposes. This takes away from the blood that is available for transporting oxygen to your exercising muscles. Increasing your blood supply gives you more blood to “ go around”. If you increase your blood volume you also increase the total amount of water that you carry in your blood vessels. This may allow you to have some increased reserves against dehydration. Studies have clearly shown that blood loading increases heat tolerance. If you heat train you also increase your total blood volume and this may help your performances in cold weather as well as hot weather. This gives you some of the advantages of blood loading, though with heat training you don’t increase your hematocrit.