Effects of exposure to simulated high altitude on red-cell 2,3-DPG, salivary cortisol and plasma testosterone levels during training in female swimmers / 体力科学

ABSTRACT

Thirteen female swimmers (ranging in age from 15 to 18 years) were selected as subjects and divided into two groups; group A (subjects of experiment) consisted of six subjects in whom low pressure was loaded and group B (subjects of control) consisted of seven in whom low pressure was not given.<BR>During training, circuit weight training was performed in a low pressure environment and it was combined with conventional swimming training. We studied the effect of these types of training on their red-cell 2, 3-diphosphoglycerate, salivary cortisol, and plasma testosterone.<BR>(1) The 2, 3-DPG level showed a greater increase after loading exercise than at the time of resting in both groups A and B. The increase was highly significant in group A. Additionally, 10 days after the removal of the loading, hemoglobin and hematocrit levels were significantly decreased in groups A and B, and a significant increase in 2, 3-DPG was observed in group A.<BR>(2) Only after loading low pressure was the cortisol level higher in group A than in group B. However, there was no significant difference between the two groups in the amount of exercise loading when heart rate was used as the index.<BR>(3) Testosterone tended to show a greater increase after exercise loading than on the first day of the experiment. However, neither an effect of exposure to low pressure on testosterone nor a significant difference between the two groups was observed.<BR>According to the results, in swimming, an endurance contest, physical changes during training are almost the same in group A and B, but it is considered that a concurrent severe hypoxic condition as a result of low pressure loading brings about homeostasis in the living body and the homeostasis leads to an attempt to increase oxygen uptake by the tissues, yeilding increased staying power.