As most know, altitude training has been a part of the competitive endurance world for the past few decades. The concept of altitude training, in retrospect, is that the athlete trains at an intermediate altitude above sea level for an extended period of time, thus causing the body to compensate for the reduced amount of oxygen by increasing the size of red blood cells and hemoglobin; as well as altering muscle metabolism such as changes in lactic acid accumulation and VO2 max. This concept has been tested many times, but is still not fully understood.
Many past studies have tested the high idea of ‘live high-train low’. It is believe that this way of altitude training allows the athlete to take advantage of the increased mass of red blood cells and hemoglobin while training or competing at sea level. However, some athletes choose to permanently live at altitude and only return to sea level for competition. The downside to this idea is that the athlete will not benefit from the workouts, as much as he or she would if the training was done at sea level as well. But, because of the difficulty of obtaining a ‘live high-train low’ environment, often times, hypobaric chambers are used to artificially place the athlete in a hypoxic atmosphere. To sum it up, altitude training, if performed properly, can be used to help improve the body’s overall efficiency during exercise, and possibly even performance.
SIGNIFICANCE OF THE PROBLEM
Although altitude training is often practiced, improvements in performance are not always displayed. This is due to the fact that ideas and concepts are not completely understood, seeing as how it is a developing training method. Scholars performing case studies that do not produce obvious performance enhancements often consider the length of time that the athletes were exposed to altitude. Also, every athlete is his or her own individual. Some will adapt enough to see improvements, others won’t.
REVIEW OF THE LITERATURE
S. Elliot conducted a literature review of an article that discussed different erythropoiesis-stimulating agents, such as altitude exposure, and how those agents are demonstrated in physical performance. It is aimed at a very knowledgeable audience with a background in physiology or biochemistry. The review explains multiple techniques of increasing erythropoiesis, and includes altitude training (living high, training low, specifically) among the ones discussed. It goes into specific detail of how, why, and to what measures erythropoiesis takes place.
JV Brugniaux et al.’s study aimed to verify whether maximal and/or submaximal aerobic performance is modified in elite middle distance runners by living high and training low; and whether the effects persist for 15 days after returning to normoxia. In a brief summary, runners were randomly ranked in two groups according to their VO2 max, which was determed at 1200 meters (2). One group lived at hypoxia and trained at 1200 meters, while the other group lived at normoxia, but also trained at 1200 meters. The study tested both groups at the end of the eighteen day period, as well as 15 days later in order to see if the effects of altitude exposure were still present.
This study practices efficient methods to produce credible results by including a control group and by measuring maximal oxygen uptake and aerobic power, ventilation and ventilator threshold, heart rate, and erythropoiesis. These results will show just how long the individual effects of altitude exposure play a role in running efficiency and performance.
In another study concentrating on distance running, CJ Julian et al. designed a case study to test the hypothesis that exposure to normobaric hypoxia is sufficient enough to cause significant physiological changes which would lead to an increase in performance. Fourteen elite distance runners were separated into two groups. One group was exposed to hypoxia for 70 min a day, five times a week, while the other group remained at normoxia at all times. The methods produced results which explain how the effects of altitude exposure on maximal O2 uptake, 3000-m time trial performance, erythropoietin, soluble transferring receptor, and reticulocyte parameters are time-dependent and do not occur overnight. This study demonstrates that positive physiological effects of altitude exposure take time and adaptation (5).
The purpose of the study conducted by P. Saunders et al. was to investigate the effect of altitude exposure on running economy. This was accomplished by assigning 22 elite distance runners to one of three groups; a “live high, train low” group, a “live moderate, train moderate” group, or a “live low, train low” group. VO2, minute ventilation, respiratory exchange ratio, heart rate, and blood lactate concentration were all assessed and tested under normoxic conditions. The results produced from this study can be used to disprove any argument that states the effects on running economy caused by altitude exposure can be matched without altitude exposure (9).
JP Wehrlin and B Marti kept their research to assessing whether hemoglobin mass increases in world class athletes when living at high altitude, and training at low altitude; and whether or not these increases are associated with peak performance during competition. Rather than using a large number of participants and having a control group, two Swiss world class runners lived 18 hours a day, for 26 days, at a high altitude and trained at normoxic conditions. The article includes results for blood variables, as well as performances by each individual runner. These results can be used to observe and confirm the physiological adaptations of altitude exposure, which lead to increases in performance and how these adaptations decrease over time after return to normoxia (10).
On the swimming side of research, B. Roels, P. Hellard, L. Schmitt, P. Robach, JP Richalet, and GP Millet assessed nine international swimmers, who trained for 13 days at either 1200m or 1850m in order to determine which altitude was significant enough produce sufficient results. Subjects were tested before and after altitude exposure. Although subjects training at 1850m showed higher mean cell volume and proportion of reticulocytes, a 2000m performance improved for subjects training at 1200m, but not for the other group training at 1850m. This could be due to the short amount of time exposed to altitude (only 13 days), implying that short term effects seem to be greater for one training at a milder degree of altitude (8). The study indicates that the benefits of higher altitudes may be delayed and appear later (8).
EY Robertson, RJ Aughey, JM Anson, WG Hawkins and DB Pyne designed a study which isolated 18 elite swimmers into four groups, with the main focus being a ‘live high, train low’ group consisting of swimmers who were scheduled to compete nationally. The study was aimed at testing the live high, train low model of altitude training and how it affects hemoglobin mass and lactate threshold.
The swimmers trained at sea level and spent the night at hypoxia. As demonstrated in other aerobic sports such as running and cycling, Hb mass increased with altitude training. However, lactate threshold actually decreased, which did not seem to explain how Hb mass increase was significant. Despite the increases in Hb mass, there were no improvements in swim times at major competitions. This leaves a lot of room for further study and investigation as to what measurements need to be taken to show an improvement in performance (6).
L. Garvican, D. Martin, M. Quoad, B. Stephens, A. Sassi and CJ Gore’s goal was to determine the time course of hemoglobin mass, erythropoietin, reticulocytes, ferritin, and soluble transferrin receptor to natural altitude training. It consisted of 13 elite cyclists who went through either three weeks of sea level or altitude training. Significant results were produced confirming that Hb mass continues to increase as long as one is exposed to altitude training, therefore increasing oxygen carrying capacity (4). Other aspects measured returned to baseline after a certain amount of days of exposure to altitude (4).
RJ Aughey et al. constructed a study which consisted of thirteen male athletes who slept at hypoxia and trained at normoxia for 23 consecutive nights in order to test the depressive effects on Na+-K+-ATPase activity, and to determine how significant the effects are on performance.
The results produced from the study were interesting, but not surprising. The only category of study that produced depressive results was ‘intense cycling exercise’ (1). This was a significant finding because it demonstrated a ~12% decrease in maximum muscle 3-O-MFPase activity (1). In reality, this would lead to a decrease in Na+-K+-ATPase activity, but only a slight depression was observed; which was not sufficient enough to cause a decline in performance (1). It is not fully understood as to the depression was not a factor in performance, but it is assumed that the nightly hypoxic exposure prevented a more significant deterioration on the number of Na+-K+-ATPase, regardless of the activity (1).
CRITICAL ANALYSIS OF THE LITERATURE
As demonstrated in the table, JV Brugniaux et al.’s study group of five distance runners showed an increase in the mass of hemoglobin, which contributed to an increase in overall effect on performance. Secondly, C. Julian et al.’s study containing a study group of 15 distance runners showed an increase in VO2 max, but there was no change in performance times after the completion. Thirdly, P. Saunders et al. created a study with seven distance runners who demonstrated improvements in VO2 max, lactic acid threshold, as well as overall performance.
Lastly for the case studies concentrating on distance runners, JP Wehrlin and B. Marti performed a study on two elite distance runners who showed a major increase in hemoglobin mass, but showed no overall increase in performance times.
As for the studies concentrating on swimming, Robertson, Anson, Hopkins and Pyne conducted a study using nine swimmers for a study group. An increase in the mass of hemoglobin was present, but the lactic acid threshold oddly decreased. There was no overall effect on performance. Secondly, Rodriguez et al used 15 athletes for their study group. An increase in VO2 max was displayed, but there no change in overall performance.
Lastly B. Roels et al. includes 9 study group members. There were improvements in VO2 max, hemoglobin mass, as well as overall performance.
As for the studies focusing on cycling, RJ Aughey et al. use six study group members whom demonstrated a decrease in VO2 max and no changes in performance times. Last but not lease, Garvican, Martin, Quod, Stephens, Sassi and Gore’s study included five athletes in the study group. However, the main area of focus was the increase in hemoglobin mass. Overall performance was not tested.
From the research discussed throughout, it should be apparent that altitude training never truly declines overall performance, and is, for the most part, always beneficial to the athlete in one or more ways. Improvements in VO2 max, hemoglobin mass, lactic acid threshold and many other elements all contribute to improvements in overall performance when necessary conditions are met.
In closing, altitude training will continue to be a large part of the endurance world as we know it, especially during times of large competitions such as national championships or the Olympic Games. However, there is still much work to be done; but from the looks of it, studies are heading in the right direction.
Altitude training is still a relatively new concept, so there is plenty of room for future research. Just because VO2 max is improved or hemoglobin mass is increased, does not mean that there is going to be an increase in overall performance (3). It would be a good idea to perform a study which contained a study group that would be exposed to altitude for a long extended period of time, versus a control group that would only be exposed for a short period of time. This is would answer many questions relating to the amount of time necessary for the body to adapt to altitude exposure.