Effects Of Phase Ⅱ Exercise Rehabilitation And CVD Risk Factors On Cardiorespiratory Fitness In Patients With Stable Coronary Artery Disease

Objective:To explore the effects of phaseⅡcardiac rehabilitation and training times on cardiorespiratory fitness in patients with stable coronary artery disease.To study the correlation between cardiorespiratory fitness and static lung function,cardiac morphology,ejection function,and muscle strength in patients with stable coronary artery disease.To explore the effect on clustering of cardiovascular risk factors on rehabilitation.Methods:The subjects were screened from April 2017 to August 2019 in patients undergoing rehabilitation in the cardiac rehabilitation room of Beijing Haidian Hospital.Collecting basic information of the subjects and testing the basic functional indicators such as height and weight.Conducting static lung function and cardiopulmonary exercise test（CPET）.According to the results,the personalized exercise prescription was made for 12 weeks of exercise intervention.Conducting CPET again after the intervention and comparing results before and after intervention.The influencing factors of cardiorespiratory fitness were analyzed by stepwise regression analysis.T test was used to analyze the difference between the two groups.ANOVA was used for the difference analysis among the three groups and above.The difference of cardiorespiratory fitness before and after intervention was analyzed by pared-samples T test.Independent-samples T test was used to compare the effects of different risk factors on the improvement of cardiorespiratory fitness.One-way analysis of variance was used to test the effect of different training times on the improvement of cardiorespiratory fitness.Results:（1）The percentage of vital capacity（VC%）,left ventricular ejection fraction（LVEF）,and right-hand grip were significant influencing factors for peak oxygen uptake（VO₂peak）.The regression coefficients were-8.508,12.298,and25.070,respectively.（2）After 12 weeks of exercise intervention,the power increased by 5.89±3.97W at AT.And the power increased 12.11±10.22W at the time of exercise to the peak,which was significantly different from that before intervention（P<0.01）.VO₂ and MET at rest were 0.21±0.66 m L/kg/min and 0.08±0.19METs lower than before intervention,respectively,with no significant difference（P>0.05）.VO₂and MET at AT were increased by 0.71±1.68 m L/kg/min and 0.21±0.47METs,respectively.There was no significant difference between them（P>0.05）.VO₂ and MET increased by 1.92±2.46 m L/kg/min and 0.53±0.71METs respectively at peak exercise（P<0.01）.（3）After 12 weeks of exercise intervention,HR and SBP decreased by 4.28±7.91times/min and 5.17±17.16mm Hg respectively,while DBP increased by0.56±12.34mm Hg.There was significant difference between HR before and after intervention（P<0.05）,but there was no significant difference between SBP and DBP before and after intervention（P>0.05）.HR,SBP and DBP decreased by 5.50±12.43times/min,6.11±22.69mm Hg and 3.33±8.38mm Hg respectively at AT（P>0.05）.HR_peak and DBP_peak increased by 1.06±12.88times/min and 0.17±9.91mm Hg respectively,SBP_peak decreased by 4.83±22.53mm Hg compared with that before intervention,and there was no significant difference in HR_peak,SBP_peak and DBP_peak（P>0.05）.（4）The VO₂peak（m L/min）of the subjects with less than 25 times of training and 25-36 times of training was significantly improved compared with the subjects with more than 36 times of training（P<0.01）.With the increase of training times,the improvement of VO₂peak（m L/kg/min）gradually increased,but there was no significant difference（P>0.05）.（5）Among the 18 subjects who completed the intervention,the VO₂peak of Q1 group was higher than that of Q2 group（21.32±3.86vs.18.78±3.17 m L/kg/min）,and there was no significant difference between the two groups.After intervention,VO₂peak in Q1 group was slightly higher than that in Q2group（22.37±4.69 vs.21.13±3.59 m L/kg/min）,and there was no significant difference between the two groups（P>0.05）.VO₂peak increased by 1.05±2.83m L/kg/min in Q1 group and 2.35±2.25 m L/kg/min in Q2 group after intervention,with no significant difference between the two groups（P>0.05）.Conclusion:（1）A 12-week systematic cardiac rehabilitation program can improve cardiorespiratory fitness in patients with stable coronary artery disease.（2）Vital capacity,left ventricular ejection fraction and right hand grip strength are directly related to cardiorespiratory fitness in patients with stable coronary artery disease.（3）When exercise intensity and single exercise time are the same,exercise frequency is the main factor affecting the improvement of cardiopulmonary endurance in patients with stable coronary heart disease.（4）12-week phase II rehabilitation exercise intervention suggested that the number of cardiovascular risk factors had a certain impact on the rehabilitation effect of patients with stable coronary artery disease.