ABSTRACT
Background: Both hypoxia exposure and physical exercise before ascending have been proved to promote high altitude acclimatization, whether the combination of these two methods can bring about a better effect remains uncertain. Therefore, we designed this study to evaluate the effect of hypoxic preacclimatization combining intermittent hypoxia exposure (IHE) and physical exercise on the tolerance to acute hypoxia and screen the optimal preacclimatization scheme among the lowlanders. Methods: A total of 120 Han Chinese young men were enrolled and randomly assigned into four groups, including the control group and three experimental groups with hypoxic preacclimatization of 5-day rest, 5-day exercise, and 3-day exercise in a hypobaric chamber, respectively. Main physical parameters for hypoxia acclimatization, AMS incidence, physical and mental capacity were measured for each participant in the hypobaric chamber simulated to the altitude of 4500 m in the effect evaluation stage. The effect was compared between different schemes. Results: During the effect evaluation stage, SpO2 of the 5-day rest group and 5-day exercise group was significantly higher than that of the control group (p = 0.001 and p = 0.006, respectively). The participants with 5-day rest had significantly lower HR than the controls (p = 0.018). No significant differences of AMS incidence were found among the four groups, while the proportion of AMS headache symptom (moderate and severe vs. mild) was significantly lower in the 3-day exercise group than that in the control group (p = 0.002). The 5-day exercise group had significantly higher VO2max, than the other three groups (p = 0.033, p < 0.001, and p = 0.023, respectively). The 5-day exercise group also had significantly higher digital symbol and pursuit aiming test scores, while shorter color selection reaction time than the control group (p = 0.005, p = 0.005, and p = 0.004, respectively). Conclusion: Hypoxic preacclimatization combining IHE with physical exercise appears to be efficient in promoting the tolerance to acute hypoxia. Hypoxia duration and physical exercise of moderate intensity are helpful for improvement of SpO2 and HR, relief of AMS headache symptoms, and enhancement of mental and physical operation capacity.
ABSTRACT
Introduction: Evidence suggests that negative cognitive processing bias (NCPB) is a significant risk factor for depression. The microbiota-gut-brain axis has been proven to be a contributing factor to cognitive health and disease. However, the connection between microbiota and NCPB remains unknown. This study mainly sought to explore the key microbiota involved in NCPB and the possible pathways through which NCPB affects depressive symptoms. Methods: Data in our studies were collected from 735 Chinese young adults through a cross-sectional survey. Fecal samples were collected from 35 young adults with different levels of NCPB (18 individuals were recruited as the high-status NCPB group, and another 17 individuals were matched as the low-status NCPB group) and 60 with different degrees of depressive symptoms (27 individuals were recruited into the depressive symptom group, as D group, and 33 individuals were matched into the control group, as C group) and analyzed by the 16S ribosomal RNA sequencing technique. Results: As a result, the level of NCPB correlated with the degree of depressive symptoms as well as anxiety symptoms and sleep quality (p < 0.01). The ß-diversity of microbiota in young adults was proven to be significantly different between the high-status NCPB and the low-status NCPB groups. There were several significantly increased bacteria taxa, including Dorea, Christensenellaceae, Christe -senellaceae_R_7_group, Ruminococcaceae_NK4A214_group, Eggerthellaceae, Family-XIII, Family_XIII_AD3011_group, Faecalibaculum, and Oscillibacter. They were mainly involved in pathways including short-chain fatty acid (SCFA) metabolism. Among these variable bacteria taxa, Faecalibaculum was found associated with both NCPB and depressive symptoms. Furthermore, five pathways turned out to be significantly altered in both the high-status NCPB group and the depressive symptom group, including butanoate metabolism, glyoxylate and dicarboxylate metabolism, propanoate metabolism, phenylalanine, tyrosine, and tryptophan biosynthesis, valine, leucine, and isoleucine degradation. These pathways were related to SCFA metabolism. Discussion: Fecal microbiota is altered in Chinese young male adults with high status NCPB and may be involved in the biochemical progress that influences depressive symptoms.
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Objective@#To investigate routine blood test results and secular changes among Tibetan children and adolescents aged from 3 to 19 in the plateau, and to provide the basis for reference range of routine blood test for this population.@*Methods@#A total of 1 568 Tibetan children and adolescents aged from 3 to 19 living in Shigatse, Tibet were selected by cluster random sampling method. Routine blood test results and its secular trends were compared by age and gender.@*Results@#Significantly differences were found in red blood cell(RBC), hemoglobin(HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin(MCH), white blood cell(WBC), neutrophil(NEU), neutrophil percentage (NEU%), lymphocyte(LYM), lymphocyte percentage(LYM%)，monocyte percentage(MON%)，eosinophil percentage(EOS%),basophil percentage(BAS%) and platelet(PLT) among the four age groups of 3-5, 6-12, 13-15, and 16-19 years ( F/H =60.22, 179.41, 249.45, 115.03, 74.90, 14.33 , 33.46, 78.90, 49.20, 97.29, 24.45,24.28,42.65,20.10, P <0.05). Among red blood cell indexes, RBC, HGB, HCT,MCH increased with age in boys( F =148.77, 493.04, 623.14, 249.92, P <0.05), but there was no similar trend in girls( F =1.37, 0.15, 2.94, 0.11, P >0.05). HCT showed significant sex differences among the four age groups of 3-5 years, 6-12 years, 13-15 years, and 16-19 years [(41.33±2.31)% vs (41.98±2.40)%; (43.28±2.60)% vs ( 43.75 ±2.36)%; (46.20±3.11)% vs (44.83±2.67)%; (51.10±4.15)% vs (43.61±4.70)%, t =-2.10, -2.88, 3.50, 10.82, P <0.05]. WBC, NEU, NEU%, LYM, LYM%, monocyte(MON), and MON% increased significantly with age in both boys and girls ( P <0.05). From the age of 12 to 13, RBC, HGB and HCT in Tibetan male and female adolescents showed an opposite trend and widened gradually.@*Conclusion@#Red blood cell index shows significantly different trends among Tibetan adolescents and children of different ages and genders. Regional nationality, age, gender, and other factors should be considered when developing the reference value range of blood routine index.
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Objective@#To investigate routine blood test results and secular changes among Tibetan children and adolescents aged from 3 to 19 in the plateau, and to provide the basis for reference range of routine blood test for this population.@*Methods@#A total of 1 568 Tibetan children and adolescents aged from 3 to 19 living in Shigatse, Tibet were selected by cluster random sampling method. Routine blood test results and its secular trends were compared by age and gender.@*Results@#Significantly differences were found in red blood cell(RBC), hemoglobin(HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin(MCH), white blood cell(WBC), neutrophil(NEU), neutrophil percentage (NEU%), lymphocyte(LYM), lymphocyte percentage(LYM%)，monocyte percentage(MON%)，eosinophil percentage(EOS%),basophil percentage(BAS%) and platelet(PLT) among the four age groups of 3-5, 6-12, 13-15, and 16-19 years ( F/H =60.22, 179.41, 249.45, 115.03, 74.90, 14.33 , 33.46, 78.90, 49.20, 97.29, 24.45,24.28,42.65,20.10, P <0.05). Among red blood cell indexes, RBC, HGB, HCT,MCH increased with age in boys( F =148.77, 493.04, 623.14, 249.92, P <0.05), but there was no similar trend in girls( F =1.37, 0.15, 2.94, 0.11, P >0.05). HCT showed significant sex differences among the four age groups of 3-5 years, 6-12 years, 13-15 years, and 16-19 years [(41.33±2.31)% vs (41.98±2.40)%; (43.28±2.60)% vs ( 43.75 ±2.36)%; (46.20±3.11)% vs (44.83±2.67)%; (51.10±4.15)% vs (43.61±4.70)%, t =-2.10, -2.88, 3.50, 10.82, P <0.05]. WBC, NEU, NEU%, LYM, LYM%, monocyte(MON), and MON% increased significantly with age in both boys and girls ( P <0.05). From the age of 12 to 13, RBC, HGB and HCT in Tibetan male and female adolescents showed an opposite trend and widened gradually.@*Conclusion@#Red blood cell index shows significantly different trends among Tibetan adolescents and children of different ages and genders. Regional nationality, age, gender, and other factors should be considered when developing the reference value range of blood routine index.
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BACKGROUND: Hypoxia-induced decline in exercise capacity is ubiquitous among lowlanders who immigrated to high altitudes, which severely reduces their work efficiency and quality of life. Although studies have revealed that hypoxia-induced cardiovascular dysfunction limits exercise capacity at high altitudes, the mechanisms have not been well explored at the molecular level. miR-199a-5p is hypoxia-sensitive and serves as an important regulator in cardiovascular pathophysiology. However, whether miR-199a-5p is involved in cardiovascular dysfunction at high altitudes and contributes to subsequent reductions in exercise capacity remains unknown. Thus, this study aimed at exploring these relationships in a high altitude population. METHODS: A total of 175 lowlanders who had immigrated to an altitude of 3,800 m 2 years previously participated in the present study. The level of plasma miR-199a-5p and the concentration of serum myocardial enzymes were detected by qRT-PCR and ELISA, respectively. Indices of cardiovascular function were examined by echocardiography. The exercise capacity was evaluated by Cooper's 12-min run test and the Harvard Step Test. Furthermore, we explored the biological functions of miR-199a-5p with silico analysis and a biochemical test. RESULTS: The level of miR-199a-5p was significantly higher in individuals with poor exercise capacity at 3,800 m, compared with those with good exercise capacity (p < 0.001). miR-199a-5p accurately identified individuals with poor exercise capacity (AUC = 0.752, p < 0.001). The level of miR-199a-5p was positively correlated with cardiovascular dysfunction indices (all, p < 0.001). Furthermore, miR-199a-5p was involved in the oxidative stress process. CONCLUSION: In this study, we reported for the first time that the level of circulating miR-199a-5p was positively associated with exercise capacity during chronic hypoxia at high altitudes. Moreover, higher miR-199a-5p was involved in hypoxia-induced cardiovascular dysfunctions, thus contributing to poorer exercise endurance at high altitudes.
