The Effects of Age and Long-Term Endurance Training on VO2 Kinetics

Author

Tyler M. Grey, The University of Western OntarioFollow

Degree

Master of Science

Program

Kinesiology

Supervisor

Donald H. Paterson

Abstract

The kinetics of the adjustment of pulmonary oxygen uptake (VO₂) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO_2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO_2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO₂ (τVO_2p) was not different across age-groups (P > 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). For untrained, τVO_2p was greater (P < 0.05) only in the O (26 ± 7, 24 ± 7, and 42 ± 11 s for Y, M, and O, respectively). The overall adjustment of [HHb] was faster than τVO_2p in O untrained, resulting in an [HHb]/VO_2p “overshoot” during the exercise transient; this may reflect a microvascular blood flow limitation. The present study suggests that long-term endurance training can abolish the age-related slowing of τVO_2p via improved matching of local O₂ delivery to muscle VO₂.

Recommended Citation

Grey, Tyler M., "The Effects of Age and Long-Term Endurance Training on VO2 Kinetics" (2014). Electronic Thesis and Dissertation Repository. 1976.
https://ir.lib.uwo.ca/etd/1976