A Heart Rate Variability Measurement System And Heart Rate Variability Between Exercise-trained People And Common People

In modern life, people's living standard has greatly improved, but the fast pace of life can create physical and mental harm. Instead of accepting treatment after the disease, people begin to pay attention to their health in daily life. With the development of semiconductor technology, a lot of family care equipments come to people's lives.In this paper, we designed a heart rate variability (HRV) measurement system based on MSP430 and CC2500.The system realized ECG acquisition, transmission and HRV measurement. The system consists of three parts: a portable user end device, a radio frequency (RF) transceiver and PC based software. User end device as the key part of the system can run in local work mode, HRV measurement mode, RS232 or RF transmission mode. In local work mode, ECG signal is displayed on LCD. In HRV measurement mode, acquired ECG signal is filtered and heart rate, two time-domain HRV parameters are calculated and displayed on LCD. While in RS232 or RF transmission mode, ECG signal is sent via wire or wireless to PC respectively. PC based software can display, store ECG data, perform filter function, R peak recognition and HRV measurement. For RF transmission mode, we have verified its feasibility. The next step is to embed RF transmission into our system.As all we know, our body benefit from regular exercise. Through exercise training, we keep fit and strengthen autonomic nervous system. To investigate how exercise training affects autonomic nervous system,we have compared exercise-trained people and untrained people' HRV before exercise and also compared their HRV recovery after cessation of 15 minutes treadmill exercise using time-domain, frequency-domain and Poincaréscatter indices. Trained people have higher SDNN, RMSSD, HF and SD1 than untrained people before exercise; trained people have higher HF norm and SD1/SD2, lower LF norm and LF/HF than untrained people. After exercise, trained people have higher recovery rate for HF norm and LF norm and LF/HF compared with untrained people. Results of time, frequency domain and Poincaréscatter method show that exercise-trained people have enhanced parasympathetic activity, better autonomic balance and autonomic balance of exercise-trained people is restored more rapidly compared to trained people after exercise.