Effect Of Exercise Intervention On Time Estimation In Pain State

In the past,there are relatively few studies on time estimation in pain state,and there are different opinions on the intrinsic mechanism of pain affecting time estimation.In this paper,based on the existing research,using the time estimation paradigm of reproduction method,we explore the characteristics of time estimation in pain state for subjects with different exercise experience,and explore the impact of short-term moderate intensity aerobic exercise on time estimation in pain state.Prefrontal lobe is related to executive function.Dorsolateral Prefrontal Cortex(DLPFC)is the brain area of working memory processing.Frontal polar cortex(FPA)plays an important role in decision-making and anti-interference.Previous studies have shown that exercise can activate the cerebral cortex and arouse these two brain regions.According to previous literatures,this paper hypothesizes that moderate intensity aerobic exercise can activate DLPFC and FPA brain regions,improve the working memory and anti-interference to pain of sedentary subjects,and then improve the accuracy of time estimation in pain state.Based on the above hypothesis,this experiment uses a new neuroimaging technology: functional Near Infrared Spectrum(fNIRS)to collect evidence on the level of brain mechanism before and after exercise,and takes three experiments to prove the hypothesis.Study 1: Determine the standard estimation time.There was no statistical difference in time estimation between sedentary group and exercise group.Forty male subjects,aged between 18 and 24 years old,were selected without major diseases.By using the Physical Exercise Level Scale,subjects with scores greater than or equal to43 were defined as the exercise group(20 persons),and those with scores less than or equal to 19 were defined as the sedentary group(20 persons).Six kinds of standard time(2000ms,3000 ms,4500ms,6000 ms,7500ms,9000ms)were estimated by using a 2*6 hybrid experimental design.The results showed that there was no statisticaldifference between the two groups in time estimation of 4500 ms and 7500 ms.After expert review and realistic factors,4500 ms was chosen as the standard time interval for the experiment.Study 2: To explore the difference of time estimation between the two groups under pain(7 C)and non-pain(32 C).Another group of subjects,40 males aged between 18 and 24,were recruited.Mixed experimental design of 2 x 2 was adopted.Pain and non-pain are achieved by controlling water temperature with a cold-pressing instrument.The state of pain is at 7 C and the state of non-pain is at 32 C.E-prime 2.0was used to compile the program,and the time estimation paradigm of the reproduction method was used.Two experiments were conducted on both left and right hands.Pain state and non-pain state were measured twice,10 times each time,totaling 80 trails.The total length of the experiment was about 24 minutes.Visual Analogue Scale(VAS)was used to report the pain value and the Positive and Negative Emotion Scale was used to evaluate the emotional state of the subjects.The experimental results showed that the time estimation of exercise group was more accurate than that of sedentary group.At the same time,fNIRS was used to measure the changes of blood oxygen in prefrontal lobe.Compared with non-pain state,channel 2 and channel 14 were inhibited in pain state.These two channels represent frontal pole area and dorsolateral prefrontal lobe respectively,indicating that pain inhibited the accuracy of time estimation of subjects and affected areas were as follows: Frontal polar region and dorsolateral prefrontal lobe.At the same time,the exercise group has better ability to resist pain interference,which makes the time estimation in pain state more accurate than the sedentary group.Study 3: To study the effect of short-term moderate intensity aerobic exercise on the time estimation of sedentary subjects in pain state.By comparing the two groups before and after the test,the sedentary subjects in the experimental group were given short-term moderate intensity aerobic exercise,warming up for 5 minutes,then doing moderate intensity aerobic exercise for 30 minutes,then repeating the task of timeestimation in pain state.The sedentary subjects in the control group were given 30 minutes of meditation after the time estimation task in pain state,and then the time estimation task in pain state was performed again.The differences of behavioral and brain activation levels between the experimental group and the control group were compared.The results showed that the control group did not improve the accuracy of time estimation after intervention,but the experimental group after a short course of moderate intensity aerobic exercise,the intervention effect was significant,the accuracy of time estimation in pain state was significantly higher than before intervention.It was found that channel 15 and channel 7 were activated in both States after intervention,representing the right dorsolateral prefrontal lobe and the left frontal polar cortex,respectively.It shows that short-term moderate intensity aerobic exercise can significantly activate rDLPFC,resulting in a significant improvement in the accuracy of time estimation,and FPC can improve the resistance of subjects to interference factors,thereby improving the accuracy of time estimation.Through three groups of experiments,we draw the following conclusions.1.Pain will affect the accuracy of time estimation.2.Subjects with abundant sports experience had higher accuracy of time estimation in pain state.3.Short-term moderate intensity aerobic exercise can significantly improve the accuracy of time estimation of sedentary subjects.