The Study Of HRV As A Preliminary Study Of Objective Evaluation Index Of Sub-healthy Undergraduate Students

ObjectiveRecently,scale is mainly used to evaluate sub-healthy status,the measured results have definite subjectivity,lacks of objective index to evaluate sub-healthy status.This study,to investigate the relationship between HRV and sub-healthy status by measuring the heart rate variability(HRV)indexes of healthy and sub-healthy undergraduate students,evaluates the feasibility of HRV as a objective evaluation index of sub-healthy undergraduate students,helps to establish the objective evaluation index of sub-healthy undergraduate students,offers a new approach for the diagnosis of sub-health.Methods496 undergraduate students from Guangzhou university of Chinese Medicine were selected by stratified sampling method.The research objects which matched the standard completely were evaluated the health conditions by scale diagnostics and expert qualitative diagnostics respectively through inclusion and exclusion criteria.In addition,the research objects were divided into two groups of healthy and sub-healthy undergraduate students.Expert qualitative diagnostics was used as the gold standard to discriminate the undergraduate students.The time domain indexes and frequency domain indexes of HRV of the undergraduate students were measured respectively in a calm state.The characteristics of the HRV of the ordinary undergraduate students population were analyzed from various aspects;The characteristics of the HRV indexes of healthy and sub-healthy undergraduate students were compared and analyzed.The multiple logistic regression of sub-healthy status of the undergraduate students was established.The ROC curve of HRV index LF/HF for diagnosing sub-healthy status of the undergraduate students was established.The sensitivity,specificity and accuracy of LF/HF diagnostics and scale diagnostics were compared.The combined application of LF/HF diagnostics and scale diagnostics was study by parallel test.Results1.There were 325 undergraduate students matching the standard completely.The healthy conditions of the 325 undergraduate students were diagnosed by scale diagnostics,including 143 undergraduate students with healthy status(44%)and 182 undergraduate students with sub-healthy status(56%).The healthy conditions of t.he 325 undergraduate students were diagnosed by expert qualitative diagnostics,including 172 undergraduate students with healthy status(52.9%)and 153 undergraduate students with sub-healthy status(47.1%).Two methods for diagnosis of sub-healthy status has significant difference(P<0.05).2.Compared with female groups,LF and LF/HF of the undergraduate students in male group were significantly increased(P<0.05);There was no significant difference among the HRV indexes of the undergraduate students of different ages(P>0.05);Compared with freshman year groups,LF/HF of the undergraduate students in sophomore year group were significantly increased(P<0.05);Compared with 1~3 times per week group,rMSSD of the undergraduate students in 4~6 times and>7 times per week group were significantly increased(P<0.05)· Compared with>7 times per week group,TP,LF and triangular index of the undergraduate students in 0 times,1~3 times and 4~6 times per week group were significantly decreased(P<0.05);Compared with>5000 m group,TP of the undergraduate students in<1000 m,1001~3000 m and 3001~5000 m group were decreased,HF of the undergraduate students in<1000 group were decreased,as well as triangular index of the undergraduate students in 1001^3000 m group,there were statistically significant(P<0.05).3.Compared with healthy undergraduate students group,rMSSD and HF of sub-healthy undergraduate students group were significantly increased(P<0.05),LF and LF/HF were significantly increased(P<0.05).Although SDNN,SDSD,TP,VLF and triangular index were in a decreasing trend,there were no statistical significance(P<0.05).4.With the standard of P<0.05,the independent variables including grade,ability of jogging,SDNN,rMSSD,SDSD,TP,VLF,LF,HF and triangle index which were not included in the regression equation was greater than 0.05.The P of the independent variables sex,exercise frequency,LF/HF which were included in the regression equation was less than 0.05.Logistic regression equation:logitP =-1.899 + 0.711 X sex-2.433 X exercise frequency(2)-2.958 X exercise frequency(3)+ 2.949 X LF/HF.The area of the ROC curve of HRV index LF/HF for diagnosing sub-healthy status of the undergraduate students was 0.788.The critical value of LF/HF for diagnosing sub-healthy status of the undergraduate students was 0.95 when the Youden index was maximum,and the sensitivity,specificity and accuracy were 62.7%,89.0%and 76.6%respectively at the moment.5.The sensitivity,specificity and accuracy of scale diagnostics were 81.0%,66.3%and 73.2%respectively.Compared with scale diagnostics,the sensitivity of LF/HF diagnostics was decreased,and the specificity and accuracy were both increased.The sensitivity and specificity of these two methods were 92.9%and 59.0%respectively after parallel test.Conclusion1.The differences of sex,grade and sports attainments of the ordinary undergraduate students ppulation are able to lead to varying degrees of changes of HRV.2.The balance of autonomic nervous system function of the sub-healthy undergraduate students is frequently decreased.3.The sex,exercise frequency and HRV index LF/HF have high correlation with sub-healthy status of the undergraduate students.The accuracy of the LF/HF diagnostics diagnosing sub-healthy status of the undergraduate students ’f’%is medium and the undergraduate students are more likely to be diagnosed as sub-healthy when LF/HF≥0.95.4.The LF/HF diagnostics may be used as an auxiliary diagnostics of sub-healthy status of the undergraduate students.