Study on the Effect of Load Exercise on Heart Rate Variability Indexes of College Students with Different Constitutions

Objective: To explore the effects of loading exercise on the heart rate change indexes of different college students, and to provide reference for further guidance of college students in choosing appropriate exercise loads during physical exercise. Methods: 20 athlete college students and 20 ordinary college students participated in loading exercise, and the exercise intensity was differentiated according to individual exercise conditions. The ECG signals were collected in the resting state and after 2 loaded exercises (primary loaded exercise and incremental loaded exercise). Time-domain parameters reflecting heart rate variability (HRV) metrics were analysed by comparison, including the standard deviation of RR intervals (SDRR), the root mean square of the difference between adjacent RR intervals (RMSSD), and the ratio of the number of beats in which the difference between adjacent RR intervals was greater than 50 milliseconds to the total number of beats (pNN50). Furthermore, frequency domain parameters, including the low frequency component (LF), the high frequency component (HF) and the low frequency component/high frequency component (LF/HF), were also analysed. The effects of loaded exercise of different intensities on the heart rate variability indexes of university students specialising in physical education and university students in general were examined in order to assess the corresponding levels of the autonomic nervous system. Results: With the increase of exercise load, the values of time domain indicators SDNN, RMSSD and pNN50 showed a decreasing trend, and the larger the load, the more significant the decrease was, and the resting state showed a highly significant difference compared with the state of incremental load exercise (P<0.01). Frequency domain indexes HF, LF, LF/HF values in the resting state compared with the incremental load exercise state were significantly different (P<0.05). Conclusion: Examining the level of heart rate variability in the athlete college students' group and the general college students' group, it was found that different loading exercise training intensities positively affected their cardiovascular system functions, suggesting that we set different levels of loading exercise training intensities according to the exercise background of the college students has a guiding significance in college students' sports.