Effects of physical training in a hypobaric chamber on the
physical performance of competitive triathletes.
Vallier JM, Chateau P, Guezennec CY
Institut de Medecine Aerospatiale du Service de Sante des Armees, Centre
d'Etudes et de
Recherches de Medecine Aerospatiale, Department de Physiologie Systemique,
Bretigny-sur-Orge,
France.
The effects of training in a hypobaric chamber on aerobic metabolism
were studied in five high
performance triathletes. During 3 weeks, the subjects modified their
usual training schedule
(approximately 30 h a week), replacing three sessions of bicycling
exercise by three sessions on a
cycle ergometer in a hypobaric chamber simulating an altitude of 4,000
m (462 mm Hg). Prior to
and after training in the hypobaric chamber the triathletes performed
maximal and submaximal
exercise in normoxia and hypoxia (462 mm g). Respiratory and cardiac
parameters were recorded
during exercise. Lactacidaemia was measured during maximal exercise.
Blood samples were drawn
once a week to monitor blood cell parameters and erythropoetin concentrations.
Training in the
hypobaric chamber had no effect on erythropoiesis, the concentrations
of erythropoetin always
remaining unchanged, and no effect on the maximal oxygen uptake (VO2max)
and maximal aerobic
capacity measured in normoxia or hypoxia. Submaximal performance increased
by 34% during a
submaximal exhausting exercise performed at a simulated altitude of
2,000 m. During a submaximal
nonexhausting test, ventilation values tended to decrease for similar
exercise intensities after training
in hypoxia. The changes in these parameters and the improved performance
found for submaximal
exercise may have been the result of changes taking place in muscle
tissue or the result of training the
respiratory muscles.