Cardiac reserve mobilization trend during exercise and recovery after exercise

Objective: Little is known about the cardiac contractility recovery after exercise. The objective of the study was to explore a method to evaluate the extent and speed of cardiac function up-regulation during exercise and the recovery course of cardiac contractility and heart rate after exercise. Methods: Ten student athletes and ten student non-athlete voluntarily participated in this controlled study. Three indicators were selected: 1) amplitude ratio of the first to second heart sound (S1/S2);2) heart rate (HR);3) power output (W). Phonocardiogram exercise test (PCGET) was adopted. A four-stage workload increment protocol was used. Phonocardiograms were recorded in the sitting position at rest and immediately after each test stage. The time taken for completing the workloads 1750 J, 3500 J, 5250 J, and 7000 J was recorded, respectively. During recovery heart sound signals were recorded immediately after exercise, and at 1, 5, 10, 15, 20, 25, and 30 minutes after exercise. S1/S2, HR, and W were calculated from the measured data. Cardiac function change trend graphs were constructed. Results: During exercise, HR and S1/S2 ratio increased with the increase in workload from 1750 J to 7000 J;the level and speed of increase in power output and S1/S2 ratio of the athletes were higher than the general students;power done by the general students decreased earlier than the athletes. During recovery course, the recovery course of the general students was slower than the athletes. Conclusion: This method for evaluating cardiac function up-regulation and recovery course is safe, easy, reliable, and effective, which is beneficial for selecting athletes, training, and matchmaking.

Measurement of two new indicators of cardiac reserve in humans, rats, rabbits, and dogs

Background: It is difficult to observe the phenomena of cardiac fatigue under a low or moderate workload test, and little was reported about cardiac fatigue under a heavy workload test because of the potential risk (sudden death) of prolonged strenuous exercise. Animal experiments would be helpful to resolve this problem. The objective of this study was to obtain baseline data of two new indicators of cardiac reserve in rats, rabbits, and dogs. Methods: Ten New Zealand White rabbits (1. 5 to 2 kg, 4 females), 10 male Wistar rats (2 months old), and 10 Golden Retriever dogs (40 days old, 5 females) were included in this study. Phonocardiogram of each animal was recorded. The basic points concerning heart sound quantitative analysis were: 1) measuring the duration and the amplitude of relevant heart sound components;2) calculating and analyzing relevant indicators based on the data obtained from the above measurements, including the ratio of diastolic to systolic duration (D/S) and the ratio of the amplitude of the first heart sound to the amplitude of the second heart sound (S1/S2). Results: The baseline data of D/S ratio and S1/S2 ratio in rats, rabbits, and dogs were obtained. The swimming time to exhaustion for rabbits was several to a dozen minutes, and for rats, several hours. Conclusion: D/S ratio has an important biological implication, which is a safe and easy indicator for evaluating the cardiac health status of both animals and humans.

基于肢体和心脏功能储备动用趋势的运动员体能评估五线图方法的初步研究

提出和探讨一种安全、易于普及的、基于运动员肢体和心脏功能储备评估的方法。方法:15名足球运动员(A组)和18名非运动员(B组)自愿参加该项研究。所有受试者进行登梯试验,根据总运动量7 000J,平台高度(0.23m)和体重(kg)确定登梯次数;试验按运动量1 750J,3 500J,5 250J和7 000J分为4个阶段。运动前和每一运动阶段结束即刻记录心音图。用肢体和心脏功能储备的5个指标进行综合分析:1)登梯运动中的人体功率输出(Power);2)登梯运动的代谢当量的评估值,公式(美国运动医学学会,ACSM):VO2(ml.kg-1.min-1)=0.2(steps.min-1)+(step height,m×steps.min-1×2.4)+3.5,代谢当量(MET)=VO2/3.5;3)第1心音幅值/第2心音幅值比值(S1/S2);4)心脏舒张期时限与收缩期时限的比值(D/S);5)心率(HR)。以运动量作横坐标,上述5个指标作纵坐标,绘制5个测试点数据的五线图。测量对应于1 750J的线段与横坐标轴(X轴)的夹角;比较5线的走向和点数据的大小,进行受试者运动能力的分析。结果:生成了受试者运动量递增的登梯试验的Power,MET,S1/S2,D/S和HR五线图。A组和B组受试者完成1 750J运动量时Power,MET,S1/S2,D/S和HR五线与X轴夹角的平均值分别是76°,72°;75°,71°;38°,35°;-8°,-6°;55°,54°。不同受试者在相同运动量下Power,MET,S1/S2,D/S和HR数据呈现有一定趋势的差异,与非运动员比较,运动员的Power,MET,S1/S2和D/S水平较高,而HR水平较低,上升较慢。结论:完成1 750J运动量时,Power线,MET线,S1/S2线与X轴的夹角可能有益于评估受试者的爆发力;5条线的走向和点数据的大小可能有益于评估受试者的耐力。