As heart rate is one of the major indications of human cardiovascular response to exercises, it has been applied for the assessment of cardiovascular fitness and monitoring of rehabilitation exercise with a focus on cardiovascular abnormality detection. In sport training, medical diagnosis, rehabilitation and analysis of cardio respiratory kinetics, automated exercise testing systems have revealed their growing importance. These systems can fully implement programmed exercise and training protocols to achieve desired exercising and testing results. In these automated systems, treadmill speed and elevation can be controlled so that an exerciser’ heart rate accurately track a desired preset heart rate profile. This will ensure that people are exercising within their personal heart rate training zones and hence achieving maximum efficiency. This study aims to develop a portable adaptive heart rate monitoring and controlling system to supervise the high intensity treadmill exercises. During training or rehabilitation exercises, the intensity (measured by heart rate) is regulated by simultaneously manipulating both treadmill speed and elevation. As the system is designed for a dynamic range of treadmill exercise intensity (from mild walking exercise to high intensity running exercise) and is suitable for various exercisers (from rehabilitation patients to athletes), the main challenge of this study is the development of ’a nonlinear adaptive controller which can adapt itself to handle system uncertainties and high nonlinearities. Based on the combination of PID and wavelet neural network controllers, an adaptive control system has been developed to achieve robust tracking performance under various training requirements. As a result, PID controller ensures the stability of the controlled system while wavelet neural network controller improves system performance under model uncertainties and unknown external disturbances. Real-time experimental results confirm that desired performance of the overall system under various exercisers and a dynamic range of exercise intensity can indeed be achieved.