So does spinach contain iron ?
Is altitude beneficial to health in general and physical performance in particular? This question has been plaguing scientists for a long time.
In 1962, a study (Reynafarje 1962) showed that persons living at a high altitude had a capillary concentration 30% higher than persons living at sea
level. This study unfortunately influenced thinking and research by physiologists for almost 30 years. Other studies subsequently confirmed those results and the idea that altitude was, in itself, good for the body, gradually became commonplace. Some doubt was cast on the theory in 1987 (Banchero 1987) when Bachero arrived at different conclusions and brought into question the research method used. After an expedition to the Himalaya, H. Hoppeler (Hoppeler 1990) observed, inter alia, a reduction in the muscle mass of mountaineers who returned from a very high altitude. Other studies subsequently confirmed those observations. It is now a generally accepted fact that the increase in capillary density observed in 1962 is due to a reduction of the muscle mass. The same capillary count in a severely atrophied muscle gave the false impression of a higher count.
We know now that at high altitudes (above 5,500m), instead of acclimatizing, the body actually deteriorates. This finding has caused mountaineers to change their approach so as to reduce time spent at very high altitudes as much as possible. Unfortunately, as with the myth that spinach contains iron, the idea that high
altitudes are good for the body still remains ever-present in some minds. But things are not as simple as that.
Altitude training courses
After the Olympic Games in Mexico, many people became interested in the effects of altitude on athletic performance. Hence the idea of altitude training courses was born. It was a veritable gold rush. The hope was that altitude would increase haematocrit value, thereby subjecting the body to positive stress.
The results were very quickly disputed and no scientific study was able to confirm altitude-enhanced physical performance. This can be explained first of all by the fact that, in order to increase red blood cell count as well as haematocrit value, several weeks of exposure are required. Two or three weeks simply do not suffice. Secondly, few are aware that, at altitude, training load should be reduced and exercise duration increased. A scientific study (Billat and Gazeau 2003) recently illustrated that time limit increased as maximum anaerobic power decreased. Therefore, there is a risk of over- training. Finally, there is a quasi- consensus on the fact that traditional altitude training courses did not live up to expectations.
The advent of recombinant EPO…
Research in performance enhancement due to higher red blood cell count went haywire. First, there was self- transfusion. A few months prior to big sporting events, athletes would draw blood which they would keep. Few days before the competition, they would inject themselves with the red blood cells. The results were spectacular. A higher number of oxygen carriers delivered more oxygen to the muscles, thereby resulting in higher endurance. This dangerous method (high haematocrit value) was banned by the IOC. Nevertheless, the debate was far from over and when EPOr became available on the market, it was widely used by
athletes. No one disputes the effects of higher haematocrit value on performance. However, the serious risks involved are not as well-known. Anti- doping efforts, particularly those targeting the use of EPOr, made significant gains when tests were developed to detect the substance in the body.
Night altitude
Once the limits of altitude training courses process became known, some began to explore the idea of using altitude for periods of rest only, essentially at night. To this end, hypoxic chambers (hypoxia = reduced oxygen) or Finnish “altitude houses”, were developed and first used in Nordic countries and in the East. The concept
consists of spending 8 to 10 hours in simulated altitude conditions in order to increase the natural EPO rate, while maintaining normal activity during the day at low altitude. The protocol is known as “sleeping high-training low”. To be truly effective, the regimen must be followed over several weeks. Four weeks are not enough to increase the red blood cell count. Many people are deluded by the haematocrit value, which is but a ratio of solid mass to liquid volume. At altitude, we tend to speak of losing fluids. This is as a result of haemoglobin concentration which causes a higher haematocrit value to appear. This does not, however, mean a higher red blood cell volume. All studies that have used the CO2 rebreathing method (red blood cell count in the body) have shown that the increase in red blood cell count was either nil or insignificant up to 28 days with this regimen. Notwithstanding this evidence, some continue to think that two or three weeks of training using this protocol is beneficial to athletes.
Altitude or intermittente hypoxia at rest
The concept originated in the former USSR and consists of subjecting the body to intense hypoxia (6,000m altitude) for a few minutes, reverting to sea level for a few minutes and repeating the process several times. Apart from some Russian publications, few scientific studies have been conducted in this area. Similar protocols require rest of between 60 and 75 minutes at an altitude of 5,500m. This still brings into play intense, short-term, intermittent hypoxia. Certain physiological mechanisms are associated with the hypoxia-inducible factor 1 (HIF-1), as with active hypoxia. However, this method is between three and ten times less effective than hypoxia combined with exercise.
A novel approach : active hypoxia – The AltiTrainer method
In 1990, N. Terrados (Terrados 1990) came up with the hypothesis that exercise is a double stimulus for oxidative enzymes and myoglobin and was more effective than the mere combination of both effects. A groundbreaking experiment opened the way for a novel approach. It consisted of exercising one leg first in hypoxic conditions and then exercising the second leg in normoxic conditions. Other studies followed (Terrados 1992, Desplanche and Hoppeler 1993) and showed distinctly enhanced performance as well as improvements in physiological parameters such as higher VO2max and higher time limit without altering blood parameters. Molecular biology today allows us to understand these mechanisms and, in particular, the major role played by the hypoxia- inducible factor-1 (HIF-1). We know that HIF-1 deteriorate rapidly in normoxic conditions and that, conversely, hypoxic conditions protect them, thereby enabling them to release their full effects as follows: higher intramuscular myoglobin, vascular endothelial growth factor (VEGF), glycolytic enzymes such as phosphofructokinase (PFK), increased capillary vascularity and mitochondrial density (Hoppeler and Vogt 2001).
It was clearly illustrated that exercise associated with hypoxia had effects that neither hypoxia nor exercise on their own could produce. It is the combination of these two factors, altitude plus physical effort, that produces these remarkable results (Hoppeler 2001). Based on these scientific findings, active hypoxia is superior to all other forms of hypoxia use in terms of performance enhancement. In fact, when the body is subjected to the double stress of exercise and hypoxia, it triggers regulatory mechanisms to compensate for the reduced oxygen supply, thereby increasing the availability of oxygen to muscles in particular. These regulatory mechanisms continue to release their effects on return to sea level, hence increased oxygen availability and enhanced performance. These mechanisms remain effective at least three weeks after training has ceased, and lose their effect after three months.
A simple & reliable protocol
The AltiTrainer method consists of exercising at altitude for a limited duration, followed by recovery at sea level and continuing the remainder of the exercise program at low altitude. In concrete terms, exercise is carried out at an altitude of approximately 2,500m at the anaerobic threshold (lactate threshold) for 30 to 40 minutes one to two times a week. The results are very quick – already after two weeks the training load has to be increased as the anaerobic threshold shifts. In top level athletes, 8% increases in VO2max and 35% increases in time limit have been observed in the final stage of preparation.
One equipment : AltiTrainer
AltiTrainer est une nouveauté qui commence à se faire connaître au niveau international. AltiTrainer permet de pratiquer un entraînement en hypoxie sur un tapis roulant ou un vélo fixe en toute simplicité. AltiTrainer est conçu pour délivrer les grandes quantités d’air hypoxique nécessaire à un sportif de haut niveau en plein effort ( jusqu’à 200 litres par minute) L’altitude de travail peut être librement choisie et contrôlée grâce à un microprocesseur associé à une sonde à oxygène. AltiTrainer associe fiabilité, efficacité, simplicité et économie.