Cardiorespiratory response to aerobic exercise programs with different intensity: 20 weeks longitudinal study

Abstract

• Context: participation in regular intensive exercise is associated with a modest increase in left ventricular wall thickness and cavity size. The magnitude of improvement depends on frequency, intensity, type, and duration of exercise program. 
• Aims: to determine the effect of sports training on LV morphology and function, lung function, and to know the intensity of the exercise program enough for these changes.
• Settings and design: this was a longitudinal study (20 weeks duration) done on the medical college students.
• Material and methods: three groups, doing exercise at different intensities, high intensity group (HG) [74.9±3.9 %HRmax], low intensity group (LG) [59.46±4.1%HRmax] and no exercise group (NG) were made, and their assessments were done using the echocardiography and pulmonary function test three times, first before start of the exercise program, second at the end of 10th week, and then at the end of the 20th week.
• Statistical analysis used: 3 × 3 Anova test and Bonferroni’s post-test using Graph pad prism5 software.
• Results: significant improvement was seen in HG in majority of cardio respiratory parameters (VO2max, heart rate, LVIDD, LVIDS, EDV, MVV, PEFR, FVC) as compared to the LG (VO2max, heart rate, MVV, PEFR) and this improvement was specially seen at the end of the twentieth week. Conclusions: twenty weeks of training is helpful in improving aerobic power, MVV, and PEFR even the exercise is of moderate (LG) to high intensity (HG) but for overall cardio respiratory development physical training must be associated with very hard intensity if duration of the exercise program is short.
• Key words: left ventricular Internal diameter at end-diastole, left ventricular Internal diameter at end-systole, end diastolic volume, ejection fraction %, maximum voluntary ventilation, peak expiratory flow rate, forced vital capacity