Effects of multiple factors on denitrogenation of human body

Abstract

Objective To discuss the regular pattern of human body's denitrogenation under such multiple factor influences as low pressure,exercise and breathing enriched O2 and to conclude the effect of denitrogenation.Methods Four subjects were tested upon 3-factor 2-level orthogonal experimental design for four times.Experimental factors were the concentration of inspired oxygen (60％ and pure oxygen),simulated altitude (ground level and 3000 m),exercise stress (meditation,and 40W).The expiratory gas was collected in an air bag and the concentrations of N2,O2,CO2 were measured by mass spectrograph.The pulmonary ventilation volume and heart rate were measured by MP150 system.40 W exercise stress was offered by a power bicycle.Results In these test conditions the decreasing order of the factors affected denitrogenation was inspired oxygen concentration,exercise stress and low pressure environment.Variance analysis showed that the effects of inspired oxygen concentration and exercise stress on the denitrogenation had statistical significance (F=19.04,17.05,P＜0.01).The interactions of oxygen concentration and low air pressure,as well as oxygen concentration and exercise promoted the effect of denitrogenation (F=5.78,4.76,P＜0.05).Conclusions Exercise and low pressure environment could promote the denitrogenation from body and the lower oxygen concentration inspired the more obvious promotion effect gained. Key words: Oxygen; Nitrogen; Altitude; Decompression sickness; Exercise; Air pressure