ALTITUDE AND HYPOXIA TRAINING - A SHORT REVIEW

The importance of oxygen transport and consumption in the body for end urance performance is the reason why altitude training as preparation for competitions at sea level has become popular. In hypoxia maximal O -2 uptake decreases, Thus for equal work load training at altitude is harder and stimulates adaptation processes more than sea level trainin g. A specific altitude training effect, however, can only be proven if a relative equal load (in % of (V) over dot O(2)max) is more effectiv e than during sea level training. In only three of 10 investigations w ith this design has a significant improvement of either maximal perfor mance, (V) over dot O(2)max or endurance been found, in two there was a nonsignificant tendency. When training in hypoxia combined with livi ng in normoxia was investigated two of four groups improved. Living in hypoxia with training in normoxia is probably more effective but only preliminary publications are available. Summarizing, a small specific altitude effect on performance capacity seems to exist, which may be counteracted by negative influences like reduced stimulation of muscul ar metabolism. A series of single physiological changes at altitude mi ght have positive or negative implications on training success: traini ng of respiratory muscles, increase of hypoxic ventilatory stimulation , reduced heart training by vegetative ''braking'', increase of red ce ll and plasma volume (the latter after descent), right shift of the ox ygen dissociation curve, increase of oxidative muscle enzymes (only af ter hypoxia training), shift from fat and muscle glycogen to blood glu cose combustion, reduced lactic acid and ammonia production, increase in buffer capacity.