Improved cardiovascular health and cardiorespiratory fitness assessment using the cycle ergometric exercise induced cardiovascular variability

Abstract

An exercise stress test is an advanced clinical method to diagnose cardiovascular diseases and to as-sess cardiorespiratory functional capacity for the purpose of guiding cardiovascular and pulmonary diagnoses and therapies. In most cases, the exercise test was conducted by either exercise on a treadmill or pedaling a cycle ergometer using maximal or submaximal test protocols. However, because conventional maximal and submaximal test protocols aim to achieve a higher level of heart rate (typically, at least 70 % of heart rate reserved or 85 % of maximum heart rate), it may be difficult to apply these protocols to inactive individuals, such as children and the elderly. Furthermore, the exercise test conducted on inactive people may provide inaccurate and unreliable results because of local muscle (e.g. quadriceps) fatigue during the exercise. To cope with these problems, a new cycle ergometric exercise test protocol equipped with fixed low and mod-erate workloads is proposed. The fixed workloads make the exercise test simple because physicians and exer-cise physiologists do not need an additional measurement to estimate individual’s fitness level to provide proper exercise test workloads. The low and moderate workloads further allow users, even for inexperienced and inactive people, not only to conduct exercise tests safely but also to elicit the cardiovascular autonomic function more clearly. This is basically motivated from the fact that an increased cardiac sympathetic activation is maximized when the heart rate reaches approximately 100 bpm while the parasympathetic tone is virtually diminished at a peak exercise, which is attainable with the proposed exercise test protocol. Most conventional exercise tests measure the ECG, the heart rate, and the blood pressure, and then derive analyzing parameters, such as one-minute heart rate recovery (HRR) and the percentage of age-adjusted maximum heart rate, to diagnose cardiovascular diseases and to assess the cardi...