Work of Breathing during Exercise in Healthy Young Men and Women

Abstract

Non-elastic work of breathing on the lungs was calculated on line with an analog computer from respiratory air flow and its driving pressure in 10 healthy young women and 10 healthy young men. The non-elastic work was found to increase as a power function of total ventilation and as an exponential function of work load. The least square regression for non-elastic work, W_{non el}, kpm/min on total ventilation V_E (ATPS) was W_{non el}=0.00065 · V_E^2,37 for the women and W_{non el}=0.0013 · VE ^2.11 for the men. These data agree well with those of earlier investigations. The study shows that the W_{non el} at the same submaximal loads is the same for the men and women. The men, however, reach a higher maximum than the women. The relationship between highest observed W_{non el} in women and men is 0.65, which is the same as the relationship between the working capacity expressed as the rate of work at a heart rate of 170 beats per minute for the men and women.

Key Words:

• Analog computer
• exercise
• normal subjects
• work of breathing