Heart rate dynamics with the applications into a quantitative evaluation of improvements on cardiac stress endurance after high intensity interval training in healthy men

In this paper, we adopted a Cardiac Stress Index (CSI) to quantitatively evaluate improvements of cardiac stress endurance after high intensity interval training in healthy men. We measured the changes in CSI curves after a 5-week cycling-based endurance training protocol that involved four repeated bouts of 4-minute high intensity effort followed by 3-minute active recovery. Seven healthy men ranging from 22 to 24 years old were recruited for undergoing the bipedal cycling endurance training. Each participant was asked to do ten-minute warm-up exercise to prevent sports injuries. We then incorporated the CSI into a cycling based cardiac monitoring system so the cardiac stress can be continuously and quantitatively assessed for the subjects undergoing the endurance training. The entire high intensity interval training process was performed three times a week and had lasted for five weeks. To conclude, numerical analysis results produced by the present study showed that CSI measures were reduced more after performing a 5-week endurance training compared with those obtained at the start phase of the training, indicating the cardiac stress endurance may be improved.