The influence of exercise intensity on cardiorespiratory function in the sedentary elderly with coronary heart disease / 中华物理医学与康复杂志

ABSTRACT

Objective To observe the influence of exercise intensity on cardiorespiratory function in the elderly with coronary heart disease using simplified 24-action Taijiquan and jogging. Methods A total of 115 sedentary elderly patients with heart disease were randomly divided into a control group ( no exercise), a low-intensity exercise group, a medium-intensity exercise group (whose exercise was simplified 24-action Taijiquan at 40-60% of their individual maximum oxygen consumption (VO2max) for 90 to 200 minutes per week) and a high-intensity exercise group ( whose exercise was jogging on a treadmill at ＞ 70% of their maximum oxygen consumption for 200 minutes per week). The regime was maintained for 6 months. All patients accepted a treadmill exercise test before and after the 6 months of exercise to evaluate the changes in VO2max, maximum heart rate ( HRmax), VO2max/HRmax and exercise time (t). Results ( 1 ) After 6 months of exercise, VO2max, HRmax, VO2/HRmax and t had increased sisnificantly in all three exercise groups. Work capacity had increased 18.6% , 33% and 34.4% and HRmax had increased 9.3% , 13.8%, 19.1%. There was no difference between before and after in the control group. (2) Compared with the control group the average VO2max, HRmax and t of all three exercise groups had increased significantly. VO2 max was 9.4% , 26% and 23. 1% better; HRmax was 6.7% , 8.8% and 12% better; t was 3.5,4 and 4.9 minutes longer. (3) Compared with the low-intensity exercise group, VO2max, HRmax and t in the medium- and high-intensity groups increased significantly more. VO2max increased 16.6% and 13.7% more; HRmax increased 2.1% and 3.2% more and average t was 0.5 and 1.4 minutes longer. (4) There was no significant difference between the medium- and high-intensity exercise groups in terms of VO2max. (5) The incidence of self-reported adverse responses to exercise such as dizziness, chest stuffiness and fatigue in the high-intensity exercise group increased significantly compared with the other 3 groups. Conclusions Exercise can gradually improve cardiorespiratory function in the sedentary elderly with heart disease. The effects of medium-intensity exercise are similar to those of high-intensity exercise, but medium intensity is safer.