Effects Of Acute High Intensity Interval Training And Moderate Intensity Continuous Training On Vascular Endothelial Function And Cognitive Performance In Sedentary College Students

Object:Sedentary behavior is an important risk factor for morbidity and mortality from NCDs,and a chronically sedentary and inactive lifestyle can lead to impaired vascular endothelial and cognitive function.Acute aerobic exercise can improve cardiovascular as well as cognitive function to some extent.Moderate-intensity continuous training has become the most common type of aerobic exercise with its wide range of applications and moderate intensity,while high-intensity interval training has become more popular in recent years with its short duration and high efficiency.HIIT has gradually gained attention in recent years because of its short duration and high efficiency.For sedentary people who do not have enough time to exercise,MICT takes a long time to perform and does not seem to be an appropriate choice,and it is worth exploring whether HIIT,with its short duration and high efficiency,is suitable for sedentary people.This study evaluates and compares acute HIIT with MICT exercise as an effective intervention to improve vascular endothelial function and cognitive performance in a sedentary population,and explores the underlying mechanisms.Methods:Fifteen college students over 18 years of age with sedentary behavior were recruited and three intervention trials,sedentary group,HIIT group,and MICT group,were randomly selected.The exercise mode was power cycling,and the HIIT group was 20 min of high-intensity intermittent exercise with alternating intervals of 40%-80%of maximal oxygen uptake（VO₂max）;the MICT group was 40 min of moderate-intensity exercise with 40%of VO₂max.one-week washout period and real-time heart rate monitoring were performed at the time of intervention.The sedentary group had a1-h sedentary intervention.Before and after the intervention,the subjects were tested for relevant functions,and samples were collected:（1）The flow-mediated dilation（FMD）function was tested.（2）Switching,Stroop,and N-back tests were carried out and the reaction time and correct rate of the subjects were collected.At the same time,the NIRX near-infrared brain function imaging system was used to monitor hemodynamic changes in the prefrontal cortex under different conditions of the task state.（3）Blood lactic acid and fingertip blood were collected in real time before and after the intervention.（4）The concentrations of vascular endothelial growth factor（VEGF）,insulin-like growth factor-1（IGF-1）,brain-derived neurotrophic factor（BDNF）,and irisin in the plasma of the three groups were quantitatively detected by enzyme-linked immunosorbent assay.Results:（1）Compared with the SIT group,FMD was significantly increased between the HIIT and MICT groups,and there was no difference between the HIIT and MICT groups.（2）In the Switching test,compared with the SIT group,the accuracy of the HIIT group increased significantly after the intervention,and the accuracy of the SIT group decreased significantly within the group.There was no difference in response time between groups,and the response time in HIIT and MICT groups was significantly decreased.In the Stroop test,there were no between-group differences in the correct rate and reaction time after intervention,and the between-group reaction time was significantly reduced in the HIIT group compared with the SIT group.In the N-back test,there were no between-group differences in accuracy and reaction time.（3）After exercise intervention,the content of Oxy-Hb in the frontal pole region was significantly increased under the Switching condition,the content of Oxy-Hb in the frontal pole region,right dorsolateral prefrontal lobe,and the triangle of Broca’s area were significantly increased under the Stroop condition,and the content of Oxy-Hb in the right dorsolateral prefrontal lobe was significantly increased under N-back condition.（4）Compared with the SIT group,the blood lactic acid concentration in the HIIT group and MICT group was significantly increased,and the blood lactic acid concentration in the HIIT group was significantly increased compared with the MICT group.（5）Compared with SIT group,VEGF concentration in HIIT and MICT groups was significantly increased,and that in the HIIT group was significantly increased compared with the MICT group.The IGF-1 concentration in the HIIT group was significantly higher than that in SIT group.The concentration of BDNF in the HIIT group was significantly higher than that in SIT group.Irisin did not differ between groups.（6）After acute exercise intervention,the vascular endothelial index FMD was positively correlated with the change in VEGF concentration,the change in blood lactate concentration,the change in blood lactate concentration and VEGF concentration,the change in blood lactate concentration and IGF-1 concentration,and the change in VEGF concentration and IGF-1 concentration.There was a significant negative correlation between blood lactic acid concentration and the index of Switching mixture conversion reaction time,a significant negative correlation between Switching mixture conversion reaction time and BDNF concentration,and a significant positive correlation between BDNF concentration and blood lactic acid concentration.Conclusion:Acute HIIT and MICT exercise were effective in improving vascular endothelial function and executive function in sedentary people;the effects of HIIT and MICT exercise were comparable,probably due to the increase in vasodilation,cerebral blood flow,oxyhemoglobin,and blood-related factor concentrations associated with high-intensity exercise.The mechanism of the impairment of cognitive performance by sedentary behavior,which was mitigated by acute exercise,may be related to the exercise-induced production and release of blood lactate,IGF-1,VEGF,and BDNF.