RESUMO
Objective To observe the changes of the pulmonary ventilation(VE)volume under different exercise intensities along with time,and to explore the best time for measuring VE under different intensities of exercise.Methods Sixty-one young mals were selected as subjects,who engaged in exercise of different intensities on the cycle ergometer(20, 40, 60, 80, 100, 120, 140, 160, and 180 W).The duration of exercise of each intensity was 6 minutes,the cardiopulmonary function was detected using a portable instrument,and real time monitoring of VE changes was enforced. Results (1)For exercise of intensity 20 W, VE initially increased fast with time, but after 1 min,it ceased to rise and remained stable.There was no significant difference at 1 min and afterwards(P>0.05).(2)The case was the same with exercise of the intensity 40 and 60 W.(3)For intensities of 80,100,120,140,and 160 W,VE became stable at 3 min. (4)For exercise of intensity 180 W,VE became stable at 4 min.Conclusion The time taken for VE to achieve stability under different intensities is different,which is positively correlated with the intensity of exercise.The greater the intensity of exercise,the longer it takes to achieve stability.