title: Effects of aging and training status on ventilatory response during incremental cycling exercise.
abstract: The aim of this study was to examine the effect of aging and training status on ventilatory response during incremental cycling exercise. Eight young (24 ± 5 years) and 8 older (64 ± 3 years) competitive cyclists together with 8 young (27 ± 4 years) and 8 older (63 ± 2 years) untrained individuals underwent a continuous incremental cycling test to exhaustion to determine ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen uptake (VO₂max). In addition, the isocapnic buffering (IB) phase was calculated together with the hypocapnic hyperventilation. Ventilatory threshold occurred at similar relative exercise intensities in all groups, whereas RCP was recorded at higher intensities in young and older cyclists compared to the untrained subjects. The IB phase, reported as the difference between VT and RCP and expressed either in absolute (ml·min⁻¹·kg⁻¹ VO₂) or in relative terms, was greater (p < 0.01) in both young and older trained cyclists than in untrained subjects, who were also characterized by a lower exercise capacity. Isocapnic buffering was particularly small in the older untrained volunteers. Although young untrained and older trained subjects had a similar level of VO₂max, older athletes exhibited a larger IB. In addition, a higher absolute but similar relative IB was observed in young vs. older cyclists, despite a higher VO₂max in the former. In conclusion, the present study shows that aging is associated with a reduction of the IB phase recorded during an incremental exercise test. Moreover, endurance training induces adaptations that result in an enlargement of the IB phase independent of age. This information can be used for the characterization and monitoring of the physiological adaptations induced by endurance training.
authors.affiliation: Department of Human Movement and Sports Sciences, University of Rome Foro Italico, Rome, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Lenti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Vito
authors.forename: Alessandro
authors.initials: A
authors.lastname: Scotto di Palumbo
authors.forename: Paola
authors.initials: P
authors.lastname: Sbriccoli
authors.forename: Filippo M
authors.initials: FM
authors.lastname: Quattrini
authors.forename: Massimo
authors.initials: M
authors.lastname: Sacchetti
mesh_terms: D000222:Adaptation, Physiological; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D015308:Anaerobic Threshold / Q000502:physiology*; D000704:Analysis of Variance; D015331:Cohort Studies; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion; D012123:Pulmonary Ventilation / Q000502:physiology; D012307:Risk Factors; D055815:Young Adult