The Effect Of Aerobic Exercise At Different Intensities On Attentional Functions In High Altitude Migrants

Objective:In this study,we first conducted acute and prolonged aerobic exercise interventions of low-,moderate-,and high-intensities for acclimatized lowlanders at high altitude.The attentional networks efficiency and executive control of all participants before and after exercise intervention were collected to explore the effects of acute and prolong aerobic exercise at low-,moderate-,and high-intensity on attentional functions and whether there was a dose effect of aerobic exercise on attentional functions.In addition,by collecting aerobic capacity,brain-derived neurotrophic factor and oxygen transport capacity of all participants before and after prolonged aerobic exercise intervention,combined with behavioral data,we explored the effects of prolonged aerobic exercise on attentional functions of acclimatized lowlanders at high altitude and its underlying physiological mechanisms.Methods:In the first study,we divided the sample of 107 male adult lowlanders who had been migrated to the highlands for more than two years into four groups.Each of three groups performed 20 min of low-,moderate-,or high-intensity acute aerobic exercise,separately,and the control group watched a 20-min documentary.We used the Attention Network Test（ANT）to measure alerting,orienting,and executive control functions and the Stroop Color and Word Test（SCWT）with a different proportion of incongruent trials to investigate proactive and reactive control of executive function.In the second study,we divided the sample of 113 male adult lowlanders who had been migrated to the highlands for more than two years into four groups.Each of three groups performed 20 min of low-,moderate-,or high-intensity aerobic exercise five times a week for four weeks,separately,and the control followed their original lifestyle.Cognition（attention via the Attention Network Test and executive control via the Stroop Color and Word Test）,serum brain-derived neurotrophic factor（BDNF）levels,aerobic capacity including maximum oxygen uptake(VO_2max),resting heart rate(HR_resting),maximum heart rate(HR_max)and erythrocyte indices–red blood cell count（RBC）,hemoglobin,hematocrit（HCT）,mean RBC volume（MCV）,mean corpuscular hemoglobin（MCH）and mean corpuscular hemoglobin concentration（MCHC）were assessed pre and post intervention.Results:（1）The results of study 1 indicated that the executive control effects of the three experimental groups significantly decreased（p=0.001,p=0.000,p=0.000）and,in the posttest,the executive control effects of the high-intensity group were lower than those of the low-intensity and control groups（p=0.006,p=0.034）.Furthermore,the accuracy of the moderate-and high-intensity groups was increased significantly in the blocks containing 25%incongruent trials of SCWT task（p=0.000,p=0.006）.（2）The results of study 2 indicated that the accuracy of the moderate-and high-intensity groups was increased significantly in the blocks containing 25%incongruent trials of SCWT task（p=0.025,p=0.004）,and,in the posttest,the accuracy was higher than those of the control group（p=0.014,p=0.018）.In addition,the VO_2maxof the low-and moderate-intensity groups（p=0.000,p=0.000）and the MCV of the high-intensity group（p=0.001）were increased significantly.Furthermore,the HR_maxand MCHC of the high intensity group were decreased significantly（p=0.000,p=0.013）.Conclusions:Acute aerobic exercise at moderate-and high-intensities will improve the reactive control of executive control in acclimatized lowlanders.Moreover,prolonged aerobic exercise of moderate intensity improved reactive control and aerobic capacity,and prolonged aerobic exercise of high-intensity improved reactive control but impaired aerobic capacity and erythrocyte indices among acclimatized Tibetan lowlanders.And there was a dose-dependent effect of acute and prolonged aerobic exercise on attentional functions in acclimatized lowlanders.