Grant: Travel Awards - Institute Community Support

Breathlessness is defined as the feeling of breathing discomfort. In healthy older individuals, breathlessness is common during activities of daily living. People generally avoid exercise that causes breathlessness, leading to the adoption of a sedentary lifestyle. It is known that healthy older women report breathlessness more frequently than men, but the reasons are unclear. Important sex-differences in the structure and function of the respiratory system have been identified. Young women have smaller airways than men, even when matched for lung size. Narrower airways make it more difficult for women to breathe during exercise, which increases sensations of breathlessness and limits exercise performance. While these observations have been made in young individuals, it is unclear how such sex-difference manifest in older individuals, and how they might relate to breathlessness. Our study aimed to: i) determine if healthy aging magnifies sex-differences in the respiratory system, and ii) determine if the increased sensation of breathlessness in older women is related to sex-differences in the breathing response to exercise. Equal groups of 20 older (60-80y) and 20 younger (20-40y) healthy men and women were studied. Subjects underwent two trials, each involving detailed lung function and exercise testing. Subjects were instrumented with a specialized catheter to measure the work of the breathing muscles during the exercise. Comparisons between groups were made on the basis of age, sex, and their interactions. Our findings show that sex-differences observed in young subjects are maintained, but not magnified, in healthy older subjects. Furthermore, the differences in the work required to breathe seem to explain, at least it part, the increased sensation breathlessness in older women. The results of our study will provide important insights into the lung health of older women and an evidence-base for sex-specific plans for the management of heart and lung disease.