| Objective:This paper analyzes the HRV(heart rate variability)characteristics of trainers and untrained people in quiet state,in the whole process of sports and in the whole recovery process,evaluates the characteristics of the changes of the control ability of the body to the heart work in different states of the trained and the untrained,and provides reference for the formulation of sports programs and the prevention and control of sports risks.In addition,the influence of long-term training on the body's heart work control ability was indirectly analyzed and discussed by comparing the difference of heart rate variability between the trained and the untrained in different states.Methods:This study mainly used experimental method and mathematical statistics.The athletes of track and field team of Zhejiang Normal University were selected as the group with trainers,and the students of non Sports Majors as the group without the untrained.A continuous running of 60% VO2 max intensity was carried out for 30 minutes.In this study,mercury 4.0 running platform of H / P / cosmos company and K5 portable gas analyzer were used to test the maximum oxygen uptake of 17 men with training basis and 20 men without training basis to determine the running speed corresponding to 60% VO2 max.The first beat sports real-time monitoring system wasused to test the 60% VO2 max intensity continuous running of subjects,mainly the HR and HRV tests of subjects 30 minutes before exercise,30 minutes during exercise,60 minutes after recovery and 30 minutes on the next morning.Among them,the data of10 minutes after the test 30 minutes before the exercise was intercepted;the data of 30minutes' exercise process was intercepted,which was divided into three stages,each10 minutes was a stage;the data of 60 minutes' recovery process was intercepted,which was divided into three stages,10 minutes immediately after the end of the exercise was a stage,20-30 minutes after the end of the exercise was a stage,50-60 minutes after the end of the exercise was a stage;the data of 10 minutes after the test30 minutes on the next morning was intercepted.The values of HR and HRV time-domain(mean RR,SDNN,RMSSD,PNN50)and frequency-domain(VLF,LF,HF,TP,LF/HF,LFnorm,HFnorm)indexes obtained before exercise,during exercise,during recovery and on the morning of the next day were analyzed by means of complex measurement variance analysis and independent sample t-test.Results:(1)Before exercise,HR,time domain and frequency domain indexes of trainers were significantly higher than the untrained(P < 0.05),but the sympathetic-vagus balance of trainers did not significantly favor vagus regulation.There were no significant differences in HR,time domain and frequency domain indexes between the untrained and the untrained on the next morning,while the values of VLF and LF in the untrained were significantly higher than those before exercise(P < 0.05),and other indexes were not significantly different from those before exercise.(2)During the exercise,the HRV,autonomic nerve system,sympathetic nerve and vagus nerve system activities of the trained and the untrained decreased with the duration of the exercise(P < 0.05),and all of them decreased the most within 10 min.Both the value of LF / HF decreased in the first 20 minutes of the exercise,and increased in the 20-30 minutes of the exercise.Compared with the untrained,the trained showed advantages after 10 minutes of the exercise.The trainers' HR value was significantly lower than untrained(P < 0.01),RMSSD and LF values were significantly higher than those of untrained(P < 0.05),suggesting that the decline rateof vagus nerve activity was slower.Compared with the untrained,LF / HF value of untrained was higher in all periods of exercise,but there was no significant difference.(3)In the recovery,the time domain and frequency domain indexes of those with and without training were significantly recovered(P < 0.05).There was no significant differences in the values of SDNN and LF after 1 hour recovery,while the indexes of time domain and frequency domain did not recover to the pre exercise level within 1 hour.HR,time domain and frequency domain indexes of both recovered to the pre-exercise level after 23 hours recovery.The values of HR,average RR,RMSSD,SDNN,VLF,LF and TP of the trainers in each recovery period were significantly higher than those of the untrained(P < 0.05).The values of HF and PNN50 were significantly higher than those of the untrained in each recovery period(30 min and 60 min)(P < 0.05).But the values of LF / HF of the untrained were significantly higher than those of the untrained in each recovery period(P < 0.05).Conclusion:(1)In the quiet state,the HR of the trainers was lower than that of the non-trainers,and HRV level,sympathetic nerve activity and vagus nerve activity were all higher than that of the non-trainers,but it was not found that the balance of the sympathetic-vagus nerve of the trainers significantly inclined to the vagus nerve system.(2)In the exercise,the sympathetic nerve activity,vagus nerve activity and HRV level of the trainers and the untrained decrease with the continuous exercise.Compared with the trainers,the decline level of HRV indexes in untrained group is lower,and the balance of sympathetic-vagus nerve tends to be sympathetic nerve in the untrained group,which reflects that the heart control ability of the trained is better than the untrained.(3)In the recovery,both the trainers and the untrained show a rapid recovery trend with the increasing of time,and the HRV level and sympathetic activity of the trainers can be restored to the pre-exercise level in statistics one hour after recovery.And the impact on the exercise can be completely restored to the pre-exercise state within 23 hours.Compared with those with the trained,the recovery speed ofsympathetic nerve and vagus nerve in the untrained group is slower,and the balance tendency of the untrained group is more significant.It shows that the heart control ability of the trained is better than the untrained.(4)Sympathetic nerve activity,vagus nerve activity and HRV level all decreased the most in both the trained and the untrained patients within 10 min of exercise.The first 10 min of exercise is an adaptive stage of the heart,which should be paid attention to.During 20-30 minutes of exercise,the speed of vagus nerve activity of the trained and untrained people is slow and the decrease was small.Besides,the balance of sympathetic and vagus nerve tends to rise in this period,reflecting that the control of the vagus nerve to heart is weakened.20 minutes of exercise is the key point for the decline of the control ability of the heart,and 20-30 minutes of exercise is the key point for the decline of the control ability of the heart period.The time point and time period should be concerned. |
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