The recent Winter Olympics in Salt Lake City once again called attention to the use in endurance sports of a variety of approaches designed to increase blood hemoglobin (Hb) concentration and oxygen-carrying capacity. These approaches include altitude training or living at high altitude while training at lower altitudes, doping with the use of erythropoietin or its novel analogs, and doping with autologous blood transfusions. In these “highlighted topics,” we will review some recent and older observations concerning these issues.
Stray-Gunderson, J., R.F. Chapman, and B.D. Levine. “Living high-training low” altitude training improves sea level performance in male and female elite runners.J. Appl. Physiol.91:1113–1120, 2001. In this study, Stray-Gunderson and colleagues performed a classic study on living at high altitude and training at lower altitudes in elite athletes. The basic concept is that, although living at high altitude will be associated with many physiological responses (including increased oxygen-carrying capacity) that might be beneficial for endurance exercise performance, training at high altitude will be ineffective because the reduced partial pressure of oxygen will limit the frequency, intensity, and duration of the training effort. In other words, the high-quality training needed for elite performance at sea level will not be possible at high altitude. Therefore, the idea is to live at high altitude while training at lower altitude to maximize the altitude-associated adaptations and oxygen transport while maintaining the high-intensity training needed for elite competitive running. To address this issue, 26 distance runners (17 men and 9 women) were studied. They were all competitive at the national level in middle distance or distance races. Subjects were studied at sea level a week before and a week after 27 d of living at 2500 m. The individuals then did their high-intensity, high-velocity training at 1250 m. The rest of their training took place between 1250 and 3000 m. There were three main findings of the study. First, the 3000 m time in all subjects as a whole and in both genders improved by ∼6 s. The average for the group declined from 8:45 to 8:39. Second, run time to exhaustion during a o2max at sea level increased and o2max increased from 72.1 ± 6.9 to 74.4 ± 6.8 mL·kg−1·min−1 after the high/low-altitude training. Third, Hb concentrations increased from 13.3 ± 1 g·dL−1 at sea level before the high/low training to 14.3 ± 1.1 g·dL−1 at sea level after the high-altitude training. In general, this study demonstrates clearly that elite endurance athletes can benefit from high/low-altitude training. The idea that high intensity, high velocity training is best performed at lower altitudes to prepare for race competition while “living” and lower intensity training is performed at higher altitudes appears to be confirmed and extended by this study. Additionally, the paper contains a very nice discussion of a variety of theoretical, logistical, and practical ideas related to this topic.
It also appears, based on reports in the popular press and commercial sources, that a variety of technological strategies are being developed to facilitate high/low training in individuals who cannot reside at high-altitude locations. In this context, a variety of commercial devices, such as “altitude tents,” which permit individuals to continue to reside at low altitude while “sleeping” in a decompressed or hypoxic environment, have been developed. Information from a variety of sources suggests that “altitude tents” are available for prices as low as $6,000. Additionally, so-called “nitrogen houses” or “decompression chambers” are also being built and/or funded by a variety of sports federations and other organizations. Some countries have developed dormitories so that athletes can sleep in a hypoxic environment and continue to train at lower altitudes. Whether this strategy will be as successful as the high/low training described in the Stray-Gunderson et al. article is unclear because absolutely rigorous studies similar to the one performed by Stray-Gunderson and colleagues have not been performed with these commercially available devices. However, anecdotal reports suggest that the effects should be similar.
In summary, high/low training appears to be an effective way to enhance performance in elite athletes. It has several advantages. Principally, it appears to be “legal” in the context to rules related to doping and support. Additionally, the changes in Hb and hematocrit (Hct), although significant, are modest and are unlikely to exceed the absolute standards for Hb (16 g/dL) or Hct (50%) permitted in international competition.
ERYTHROPOIETIN AND BLOOD DOPING
The effects of erythropoietin use and blood doping on endurance exercise performance and many ethical considerations were covered in the American College of Sports Medicine Position Stand on the “Use of Blood Doping as an Ergogenic Aid” (Med. Sci. Sports Exerc. 28:i-viii, 1996). One interesting anecdotal report in the press from Salt Lake City is that some athletes used a novel erythropoietin analog called darbepoietin. This drug falls into a class of compounds called a novel erythropoiesis-stimulating protein and it is a supersialylated analog of erythropoietin. These and related compounds were developed primarily for the treatment of chronic anemia in patients on renal dialysis. Standard erythropoietin has a short plasma half-life and requires frequent dosing to treat chronically anemic patients. By contrast, darbepoietin has a higher molecular weight, which results in a severalfold increase in the half-life of the drug and permits less frequent dosing. Although there are no sport- or exercise-specific studies with darbepoietin or other novel erythropoietin analogs, it is likely that if they increase red cell mass they will enhance performance in a manner similar to erythropoietin or traditional autologous transfusion (blood doping). For those interested in more information on the basic biology of these compounds, a recent review in the American Journal of Kidney Disease (Nissenson, A.R. Novel erythropoiesis stimulating protein for managing the anemia of chronic kidney disease. Am. J. Kidney Dis. 38:1390–1397, 2001) is available. Additionally, darbepoietin was recently reviewed in the Medical Letter on Drugs and Therapeutics (Darbepoetin (Aranesp) - a long-acting erythropoietin. Med. Lett. Drugs Ther. 43:109–110, 2001).
A variety of strategies, some “legal” and others “illegal,” to raise oxygen-carrying capacity are likely to continue to be used in an effort to improve endurance performance in selected events. It is also likely that a variety of novel pharmacologic strategies will become increasingly available to manipulate these factors. Because living in a hypoxic environment can also stimulate many of these same adaptations, the current stance of many governing bodies to limit absolute levels of Hb and/or Hct seems to be the only reasonable way to regulate these practices. Interested readers are referred to the papers discussed above, which provide excellent discussions of the biology, physiology, and ethics of these practices.