Altitude Training and Endurance Performance (Part 1 of 4)
By Marc Bebich-Philip B.Sci (Sport Science)
The use of real and simulated altitude training to supplement normal endurance training at sea level has become widely used by coaches and athletes. There are numerous different altitude training models which range from living and training at moderate and high altitude to breathing hypoxic gas while living and training normally at sea level. In this 4–part series on altitude training and performance we will overview the history of altitude training and touch on the science and practice of the various models of altitude training. We also discuss the beneficial effects reported in the scientific literature and give first-hand accounts of the effectiveness of the various methods from high performance coaches. Benefits and drawbacks from each altitude method will be discussed along with advice on preparing athletes prior to altitude training.
PART 1: “A HISTORICAL AND MECHANISTIC INTRODUCTION TO ALTITUDE TRAINING”
The majority of the world’s population (80%) lives at low altitude (< 500 m) (1) which has an optimal atmospheric pressure and oxygen concentration for the human body’s functioning. As we ascend in altitude, however, the air volume expands due to the lowering of atmospheric pressure, which results in the reduction of oxygen availability to the muscular system. This drop in oxygen concentration results in decreased oxygen pressure in the air we breathe and a subsequent drop in the amount of oxygen in the blood. A reduction in the concentration of oxygen in the circulating blood results in a decreased ability to extract oxygen for the working muscles and a reduced oxygen uptake. This reduced oxygen uptake is a major problem for athletes at high altitude and is responsible for the steady decline in maximal oxygen consumption (VO2 max) and subsequent performance at high altitude. Traditional altitude training uses these oxygen concentration changes that occur with changes in elevation to induce beneficial adaptations in the performance of athletes at altitude or closer to sea level.
Research into the effects of high altitude on the human body became of great interest during the race to conquer Mt. Everest and research into the effects of altitude, particularly on exercise performance, became popular after the 1968 Olympic Games (Mexico City – 2, 300 m elevation). It was found that during the Games, endurance athletes (i.e. distance runners’) that came from sea-level countries were negatively affected by the low oxygen concentration in the air at Mexico City and struggled to win medals. On the other hand, the athletes from high-altitude based countries won many of the medals available in the middle and long distance track events. Since the Mexico City Olympic Games a plethora of research has occurred in the area of altitude training. The main focus has been to answer important questions surrounding what the optimal altitude and length of stay is and what the effects of altitude are on the physiology of the human body.
It is well known that exposure to real altitude produces a reduction in oxygen pressure in the inspired air and subsequently a decrease in oxygen-haemoglobin saturation resulting in a decrement in kidney oxygenation. This drop in oxygen concentration stimulates the synthesis and release of erythropoietin (EPO), a kidney-produced hormone, which subsequently stimulates erythropoiesis in the red bone marrow, finally resulting in increased red blood cell (RBC) and haemoglobin production. These haematological changes, over a period of time, may significantly improve aerobic capacity in endurance athletes by enhancing the transportation of oxygen to the exercising muscles and the ability of the muscular system to produce energy (2). However, debate still exists over the exact mechanisms involved in performance enhancement after altitude training. While some studies have reported increases in haemoglobin after classical altitude training (1900 m or above) (3-6), others have described no change after training at such altitudes (7-11), or at slightly lower altitudes (1740-1800) (12, 13). Indeed, recent research has indicated that performance can actually improve as a result of altitude training in the absence of any significant increase in oxygen-carrying capacity (haemoglobin concentration) (14). Gore and colleagues argue that altitude training improves exercise economy (15) through an increased ability to breakdown carbohydrates for energy production, a decreased cost of ventilation, or by an increased ability of the muscle to produce work more efficiently (16). In addition, reports from other researchers suggest an increase in muscle buffering capacity may be a possibility (17, 18). An increase in buffering capacity of the muscle or blood would allow a greater build-up of acidity during exercise, in turn allowing the athlete to exercise harder for longer before fatiguing. Potentially all of these mechanisms either solely or combined could be the cause of enhanced sea-level performance after altitude training.
- Cohen JE, Small C. Hypsographic demography: The distribution of human population by altitude. Proceedings of the National Academy of Sciences of the United States of America 1998;95:14009-14014.
- Levine BD, Stray-Gundersen J. Point: Positive effects of intermittent hypoxia (live high: train low) on exercise performance are mediated primarily by augmented red cell volume. Journal of Applied Physiology 2005;99:2053-2055.
- Levine BD, StrayGundersen J. ”Living high training low”: Effect of moderate-altitude acclimatization with low-altitude training on performance. Journal of Applied Physiology 1997 Jul;83:102-112.
- Friedmann B, Frese F, Menold E, et al. Individual variation in the erythropoietic response to altitude training in elite junior swimmers. British Journal of Sports Medicine 2005;39:148-153.
- Heinicke K, Heinicke I, Schmidt W, et al. A three-week traditional altitude training increases hemoglobin mass and red cell volume in elite biathlon athletes. International Journal of Sports Medicine 2005;26:350-355.
- Svedenhag J, Piehl-Aulin K, Skog C, et al. Increased left ventricular muscle mass after long-term altitude training in athletes. Acta Physiologica Scandinavica 1997;161:63-70.
- Dill DB, Braithwaite K, Adams WC, et al. Blood volume of middle-distance runners: effect of 2300-m altitude and comparsions with non-athletes. Medicine and Science in Sports 1974;6:1-7.
- Gore C, Craig N, Hahn A, et al. Altitude training at 2690m does not increase total haemoglobin mass or sea level VO2max in world champion track cyclists. Journal of Science and Medicine in Sport 1998;1:156-170.
- Ashenden MJ, Gore CJ, Dobson GP, et al. Simulated moderate altitude elevates serum erthyropoietin but does not increase reticulocyte production in well-trained runners. European Journal of Applied Physiology 2000;81:428-435.
- Ashenden MJ, Gore CJ, Dobson GP, et al. “Live high, train low” does not change the total haemoglobin mass of male endurance athletes sleeping at a simulated altitude of 3000 m for 23 nights. European Journal of Applied Physiology and Occupational Physiology 1999 Oct;80:479-484.
- Ashenden MJ, Gore CJ, Martin DT, et al. Effects of a 12-day “live high, train low” camp on reticulocyte production and haemoglobin mass in elite female road cyclists. European Journal of Applied Physiology 1999;80:472-478.
- Gore CJ, Hahn AG, Burge CM, et al. VO2max and haemoglobin mass of trained athletes during high intensity training. International Journal of Sports Medicine 1997;18:477-482.
- Friedmann B, Jost J, Rating T, et al. Effects of iron supplementation on total body hemoglobin during endurance training at moderate altitude. International Journal of Sports Medicine 1999;20:78-85.
- Saunders P, Telford R, Pyne D, et al. Improved running economy in elite runners after 20 days of simulated moderate-altitude exposure. Journal of Applied Physiology 2004;96:931-937.
- Gore CJ, Clark SA, Saunders PU. Non-hematological mechanisms of improved sea-level performance after hypoxic exposure. Medicine and Science in Sports and Exercise 2007 Sep;39:1600-1609
- Green H, Roy B, Grant S, et al. Increases in submaximal cycling efficiency mediated by altitude acclimatization. Journal of Applied Physiology 2000;89:1189-1197.
- Saltin B, Kim CK, Terrados N, et al. Morphology, enzyme activities and buffer capacity in leg muscles of Kenyan and Scandinavian runners. Scandinavian Journal of Medicine and Science in Sports 1995 Aug;5:222-230.
- Mizuno M, Juel C, Bro-Rasmussen T, et al. Limb skeletal muscle adaptation in athletes after training at altitude. Journal of Applied Physiology 1990;68:496-502.