title: A comparison of the ventilatory responses to exercise of elderly and younger humans.
abstract: Elderly adults are assumed to have an exaggerated ventilatory response to exercise. This study sought to examine this assumption by comparing the steady-state ventilatory and gas exchange responses of a group of elderly and younger humans. Steady-state ventilatory responses to moderate cycle ergometer exercise were measured in 14 elderly (71.0 +/- 1.3, mean +/- SEM years) and 14 younger (21.8 +/- 0.7 years) subjects. Compared with the younger group, the elderly had a significantly higher VE, VCO2, and VO2 at all work rates. In addition, delta VE/delta VCO2 was significantly higher for the elderly than for the younger subjects (31.07 +/- 1.34 vs 27.16 +/- 1.01, respectively; p less than .03), but the intercept with the ventilation axis was significantly lower (0.81 +/- 0.97 1.min-1 vs 4.15 +/- 0.77 1.min-1, respectively; p less than .015). Consequently, the VE-VCO2 relationships of the two groups crossed and the ventilatory equivalent for CO2 was similar for both groups. Thus, in these elderly subjects, the steeper delta VE/delta VCO2 was misleading because it was not associated with a greater ventilatory equivalent for CO2. In summary, although the ventilatory response of these elderly subjects to a given work rate was greater than that of the younger subjects, this was secondary to a greater metabolic requirement and cannot therefore be considered exaggerated. Furthermore, the data suggest that delta VE/delta VCO2 may be an inappropriate index of the ventilatory response to exercise in the elderly.
authors.affiliation: Department of Sport and Exercise Sciences, University of Birmingham, England.
authors.forename: A K
authors.initials: AK
authors.lastname: McConnell
authors.forename: C T
authors.initials: CT
authors.lastname: Davies
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D002245:Carbon Dioxide / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology*; D012119:Respiration / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide