| Objective:To obseRVDe the cardiac structural and functional changes of stress and adaptability to moderate plateau environment of children aged 7-13 living in plain;And explore the difference of heart morphology,structure and function between children group and adolescent group in response to the stress and adaptation of high altitude environment.Methods:Eighteen children(8 males and 10 females)aged 7 to 13 years old were selected as the study subjects,with an average age of(10.39±2.03)years old.The subjects were divided into Children Group(CG Group,n=12,male/female=7/5,average age 9.33 ± 1.6 years old)and Adolescent Group(AG,n=6,male/female=1/5,average age 12.5±0.76 years old)according to whether the females had menarche and the males had first spermatorrhea.Regular exercise was carried out for 5 weeks,in front of the plateau plain(1 week),in the plateau plain(3 weeks),at an altitude of about 2000 m,and in back of the plateau plain(1 week).The structural and functional parameters of PASP and TEI were measured by echocardiography before the plateau,2 hours after the plateau exposure,21 days after the plateau exposure and 2 hours after the plateau exposure.AMS and HAPE assessment were completed on the 1st day at the plateau.Venous blood at rest was collected on the 7th day of each week to test the content of cTnT in serum.RESULTS:Compared with pre-plateau,PASP increased significantly in both children and adolescents 2 hours after plateau exposure(F=6.046,P<0.01;F=6.091,P<0.01);IVSd of children group was significantly increased after 21 days exposure(F=1.235,P<0.05).LVIDd in children group was significantly decreased after 21 days of exposure to high altitude(F=3.711,P<0.05).LVIDs in children group were significantly increased after plateau(F=3.711,P<0.05).After 2h exposure,PA in children group was significantly increased(F=4.974,P<0.05).After 21 days of high altitude exposure,PA decreased significantly(F=4.974,P<0.01).The RVD of children group was significantly increased 2 hours after exposure(F=3.877,P<0.05);After plateau,there was a significant increase RVD of children group(F=2.782,P<0.05).The EDV of children group was significantly decreased after 21 days of exposure to high altitude(F=12.238,P<0.05),and the ESV of children group was significantly increased after exposure to low altitude(F=4.605,P<0.05).SV in children group was significantly decreased after 21 days of exposure(F=5.691,P<0.05).There was no significant change in SV in the adolescent group at each time point.CO in children group was significantly decreased after lower plateau(F=7.069,P<0.05).CO in adolescent group also significantly decreased after lower plateau(F=7.432,P<0.05).The EF of children group was significantly decreased after lower plateau(F=3.825,P<0.05).In the children group,FS was significantly decreased after 21 days of exposure to high altitude(F=5.425,P<0.05),and was significantly decreased after exposure to low altitude(F=7.060,P<0.01).The LV-TEI of children group was significantly increased continuously after 21 days of exposure to plateau and after exposure to plateau(F=7.805,P<0.01;F=8.609,P<0.01);The LV-TEI of the adolescent group also showed a continuous significant increase after 21 days of exposure to high altitude and after exposure to low altitude(F=5.785,P<0.05;F=7.465,P<0.01).The RV-TEI of children group was significantly increased after lower plateau(F=4.473,P<0.05).The RV-TEI of adolescent group was significantly increased after lower plateau(F=7.115,P<0.01);Compared with pre-plateau,hs-cTnT in children group was significantly increased 2 hours after exposure to plateau,7 days after exposure to plateau,and 14 days after exposure to plateau(F=5.675,P<0.05;F=6.685,P<0.05;F=6.685,P<0.05;F=4.982,P<0.05;F=4.982,P<0.05);Compared with pre-plateau,hs-cTnT increased significantly in the adolescent group 2h after exposure to plateau,7 days after exposure to plateau,and 14 days after exposure to plateau(F=8.075,P<0.01;F=10.005,P<0.01;F=10.005,P<0.01;F=7.975,P<0.01;F=7.975,P<0.01).Conclusion:1.Under the combined action of continuous swimming exercise and plateau environment,SV,CO,EF and FS of children group decreased continuously after 21 days of plateau exposure.The CO of adolescent group decreased after the lower plateau.2.As a whole,the plateau hypoxia and low pressure environment will have adverse effects on the heart structure and function of the subjects,especially the children group.3.In terms of the cardiovascular system,the children group is more susceptible to and difficult to recover from the altitude hypoxia environment,so it is speculated that the pre-adolescent children living in the plain are not suitable for the acute exposure and long-term learning of the altitude hypoxia environment. |
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