Adjustment of pulmonary O2 uptake, muscle deoxygenation and metabolism during moderate-intensity exercise transitions initiated from low and elevated baseline metabolic rates

Author

Joshua P. Nederveen, The University of Western OntarioFollow

Degree

Master of Science

Program

Kinesiology

Supervisor

Dr. John Kowalchuk

Abstract

When instantaneous step-wise transitions within the moderate intensity domain are initiated from elevated metabolic rates, the rate of pulmonary oxygen uptake (V̇O_2p) adjustment is slowed, and the V̇O_2p gain (ΔV̇O_2p /ΔWR) is greater. This study sought to determine the relationship between V̇O_2p kinetics and metabolic activity and energy status during step transitions from low and elevated metabolic rates within the moderate intensity domain. Ten young men completed six double-step constant load cycling bouts, consisting of step-wise transitions from 20 W to 45% θ_L and 45% θ_L [lower step (LS)] to 90% θ_L [upper step (US)], one double-step bout included needle biopsies at; baseline, steady-state values and during transitions. Gas exchange was analyzed breath-by-breath and muscle de-oxygenation status ([HHb]) was measured with near infrared spectroscopy. The V̇O_2p gain in the US (10.37 ± 1.49) was greater (p2p (τV̇O_2p) in the US (34 ± 12) was slower (pamp in the US (3.5 ± 2.6) was decreased (pfree] and [P_i] concentration was increased (p15) and remained elevated relative to baseline through the protocol.

Recommended Citation

Nederveen, Joshua P., "Adjustment of pulmonary O2 uptake, muscle deoxygenation and metabolism during moderate-intensity exercise transitions initiated from low and elevated baseline metabolic rates" (2013). Electronic Thesis and Dissertation Repository. 1555.
https://ir.lib.uwo.ca/etd/1555