title: Ventilatory responses to exercise and CO2 after menopause in healthy women: effects of age and fitness.
abstract: The extent to which aging affects respiratory control in postmenopausal women remains relatively unknown. In a cross-sectional study of 39 postmenopausal women (50-79 years), we examined the influence of age and fitness on the ventilatory responses to hypercapnia (HCVR; +8 mmHg) and exercise (ΔV˙(E)/ΔV˙CO2) above and below the anaerobic threshold (AT). Data were analyzed using the full cohort, by age (younger postmenopausal: YPM, 50-64 years; and older postmenopausal: OPM, 65-79 years) and fitness as per our previous work (Active: V˙O2max ≥90% age-predicted values; and Sedentary: V˙O2max <90% age-predicted values). Although age did not affect the sensitivity of HCVR, Active women had significantly lower HCVR gain compared to sedentary women (Sedentary: 2.12±0.80; Active: 1.57±0.73, p=0.02). In contrast, age, but not fitness, was inversely related to ΔV˙(E)/ΔV˙CO2 above AT (YPM: 46.8±11.5; OPM: 34.8±6.9, p<0.01) which may be explained, at least in part, by age-related declines in lung function. HCVR and ΔV˙(E)/ΔV˙CO2 were not correlated.
authors: Department of Physiology & Pharmacology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada. mdavenpo@ucalgary.ca
authors: Margie H
authors: MH
authors: Davenport
authors: Andrew E
authors: AE
authors: Beaudin
authors: Allison D
authors: AD
authors: Brown
authors: Richard
authors: R
authors: Leigh
authors: Marc J
authors: MJ
authors: Poulin
mesh_terms: D000367:Age Factors; D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D017698:Postmenopause / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide