Effects Of Long-term Simulated Weightlessness Exercise Training On Aerobic Capacity Of Men

Objective:Because space weightlessness flight will lead to the reduction of aerobic capacity,and in the short-term space weightlessness flight to carry out exercise training can effectively maintain the level of aerobic capacity,but currently it is lack of long-term space flight exercise training on its impact on the relevant research at home.Therefore,this experiment by establishing the model of simulated weightlessness on the ground(-6° head down bed rest),to explore in the long run to-6° head down bed rest conditions,changes of healthy men aerobic capacity,at the same time explore-6°head down bed rest exercise training intervention intervention in the role of aerobic capacity to maintain a healthy male,and verify that exercise training to maintain longterm healthy men caused by simulated weightlessness effectiveness of aerobic ability.Methods:21 subjects were randomly divided into three groups:Control group(C),Treadmill group(T)and Resistance group(R).Before the formal simulation of weightlessness,the exercise intensity tolerance experiment was carried out for the subjects in the T group and the R group for 5 days.During the experiment,the morning heart rate,blood pressure,exercise tolerance time,load intensity and other indicators were detected.After 90 days of simulated weightlessness,exercise intervention was performed on T group and R group,and indexes related to cardiopulmonary function,cardiac function and lower limb skeletal muscle circumference were tested at different time points during exercise.Results:1 The subjects could tolerate the training intensity,and there were no significant changes in heart rate,blood pressure,Borg score,exercise tolerance time and exercise load.2.There was a positive correlation between aerobic capacity and pre-VO2max,body weight,thigh circumference(TC),leg circumference(CC),and a negative correlation with age,but there was no significant correlation.3.Compared with before bed,VO2max in group C was significantly decreased(P<0.05),and the degree of decrease was 25%,31%,34%after 43 days in bed,71 days in bed,and after getting up,respectively.There was no significant decrease in group T and group R.Compared with before bed,the maximum relative oxygen uptake(VO2max/kg)in group C was significantly decreased(P<0.05),and the degree of decrease was 22%,27%,30%after 43 days in bed,71 days in bed,and after getting up,respectively.There was no significant decrease in group T and R.Compared with before bed rest,oxygen pulse(VO2max/HR)in group C decreased significantly,and the degree of decrease was 27%,32%,37%after 43 days of bed rest,71 days of bed rest and after getting up,respectively.There was no significant decrease in group T and R.The maximum heart rate(HRmax),maximum volume of gas(VEMAX)and Exercise tolerance time(ETT)were not significantly changed among all groups.4 Compared with pre-HDBR,there were no significant changes in stroke output(SV)and ejection fraction(EF)in C,T and R groups.5 TC and CC in group C were significantly decreased before and after bed bed(P<0.05).Compared with before bed bed,TC and CC in group T and R were not significantly decreased by 7.70%,9.87%and 10.88%after 42 days of bed,70 days of bed and after getting up,respectively.Conclusion:Under simulated weightlessness for a long time,aerobic capacity of healthy men decreased significantly.There was no significant change in cardiac function.The muscle circumference of the lower extremities was significantly reduced.(2)Both treadmill training and resistance training can effectively counteract the decrease of aerobic capacity during simulated weightlessness.(3)Resistance training can be used as a training method to simulate the maintenance of aerobic capacity under weightlessness.(4)Under long-term simulated weightlessness,exercise training should be increased at the early stage of bed bed to prevent the rapid decline of aerobic capacity.Aerobic capacity can be maintained through resistance training at the early and middle stage of bed bed,and aerobic capacity can be maintained through running training at the late stage of bed bed.