Effect Of Acute Aerobic Exercise On Resting-state Functional Brain Connectivity Of College Students

Objective:Compared to long-term aerobic exercise,acute aerobic load stimulation could not product obvious structural and functional changes for the body,but it could be regarded as the stimulated stressor,which is similar to mental stimulant to some extent,and it could produce certain sports benefits on cognitive function.Previous studies have demonstrated that young adults with high-level fitness showed better cognitive performance,but the brain mechanism involved remains unclear.The purpose of this study was to explore the characteristics of brain Resting State Functional Connectivity(RSFC)between the people with different fitness levels and the effects of acute load to it.Methods:According to the participants' inclusion criteria,a total of 20 high fitness level college students(High fitness Group,H Group)and 20 ordinary college students(Low fitness Group,L Group)were recruited.The motor area's blood oxygen signals in resting states were monitored by functional Near Infrared Spectroscopy(fNIRS).FC-NIRS software was used to preprocess and calculate the RSFC of the brain signals.The first research performed two resting fNIRS scans during all participants for demonstrating the difference between the people with different fitness levels.And the Intraclass Correlation Coefficient(ICC)was used to evaluate the RSFC results for test-restest reliability.The second research performed two resting fNIRS scans during all participants before and after two acute aerobic exercises(medium-and high-intensity)to explore whether acute load intensity has an impact on RSFC of college students and how does acute load affect college students with different fitness levels.Results:(1)There was a significant difference in mean value of the RSFC strength between high fitness group and low fitness group(HbO:t(38)=-3.21,P=0.003;HbR:t(38)=-3.10,P=0.004;HbT:f(38)=-4.68,P=0.000<0.05).(2)The results of the comparison of RSFC mean in the local area of the motor cortex showed that the difference between the groups of the "edges"(a total of 15 edges)formed by the first row of channels was not significant(t(15)=-1.02,df=37.76,P=0.317,FDR correction),differences between groups in the second row(a total of 28 edges,t(15)=-2.96,df=36.14,P=0.005,FDR correction)andthe third row(t(15)=-3.46,df=37.99,P=0.001,FDR correction)were significant;for HbR,the difference between the groups in the first row was aot significant(t(15)=-1.02,df=37.76,P=0.317,FDR correction),the difference between the groups in the second row(t(15)=-2.148,df=3 1.89,P=0.002,FDR correction)and the third row were significant(t(15)=-3.53,df=29.76,P=0.001);for HbT,the difference between the groups in all rows were significant(the first row:t(15)=-3.178,df=3 7.98,P=0.003,FDR c orrection;the second row:t(15)=-4.214,df=31.89,P=0.000,FDR coiTection;HbT:t(15)=-3.127,df=32.14,P=0.00,FDR correction).(3)For HbO.there were significant differences between groups in mean value of the RSFC strength in 50 edges among the 190 edges of the motor area(14 edges after FDR corrected);for HbR,there were 35 edges(0 edges after FDR corrected);for HbT.there were 110 edges(73 edges after FDR corrected).(4)At the three hemoglobin concentration signals,the mean value of group-level ICC(C,1)of the mean value of the RSFC strength in high and low fitness groups was 0.40±0.10,the mean value of group-level ICC(C,k)was 0.57±0.11.showed "fair" reliability.The mean value of group-level ICC(C,1)of RSFC strength of the 190 "edges" was 0.88±0.06,the mean value of ICC(C,k)was 0.94±0.03,showed "excellent" reliability.(5)At the three hemoglobin concentration signa,there were no significant differences in the effects of load intensity oil RSFC in college students(Integration level,HbO:F=1.92,df=2,P=0.151;HbR:F=0.51,df=2,P=0.226;HbT:F=0.65,df=2,P=0.522;High fitness level,HbO:F=1,82,df=2,P=0.172;HbR:F=0.68.df=2,P=0.510;HbT:F=1.28,df=2,P=0.185;Low fitness level,HbO:F=1.41,df=2,P=0.253;HbR:F=1.01,df=2,P=0.372;HbT:F=0.24,df=2,P=0.787).(6)For medium-intensity,acute load induced the significant differences between college students with different fitness levels in the changes of RSFC in HbO and HbT signals(HbO:F=7.46?P=0.010;HbT:F=7.313?P=0.010),further,in these two signals,acute load induced the significant decrease of RSFC in high fitness group(HbO:df=19,t=2.61,P=0.017;HbT:df=19,t=1.82,P=0.036),but these were not cased in low fitness group(HbO:df=19,t=1.13,P=0.274;HbT:df=19,t=1.82,P=0.085),and the total number of "edges" there were significant differences between sessions in high fitness group(HbP:23;HbT:24)was more than those of low fitness group(HbO:15;HbT:7).(7)For high-intensity,acute load did not induced the significant differences between college students with different fitness levels in the changes of RSFC(HbO:F=0.74?P=0.394;HbR:F=1.458?P=0.235;F=2.32,P=0.137),however,in HbR signal,acute load induced the significant decrease of RSFC in high fitness group(df=19,t=2.69,P=0.014);but this was not cased in low fitness group(df=19,t=1.57,P=0.133),and the total number of "edges" there were significant differences between sessions in high fitness group(31edges)was more than those of low fitness group(21 edges).Conclusions:RSFC strength of Motor Cortex is related to Fitness level,and higher fitness level correspond to lower RSFC strength,and vice versa;Exercise intensity was not productded the impact on RSFC;Compared with the college students with low fitness level,the impact of acute load on the students with high fitness level is more significant.RSFC might be adopted as a sensitive biomarker for the assessment of physical performance,and has better test-retest reliability;Compared with the college students with low fitness level,the impact of acute load on the students with high fitness level is more significant.the RSFC measured by fNIRS might be adopted as a biomarker for the assessanent of physical performance,and the RSFC measured by fNIRS has better test-retest reliability.At the same time,this research also provides a reference for sports workers and medical workers to formulate more efficient training programs and treatment protocols for people with different sports levels.