Oxygen uptake and heart rate kinetics during dynamic upper and lower body exercise: an investigation by time‑series analysis

Uwe Drescher, Jessica Koschate, Uwe Hoffmann

Publikation: Beitrag in FachzeitschriftZeitschriftenaufsätzeForschungBegutachtung


Purpose: The study compared the kinetic responses of heart rate (HR), pulmonary (V'O2pulm) and muscular oxygen uptake (V'O2musc) kinetics for upper (UpBody) and lower body (LoBody) exercise. Methods: Eleven healthy men (24 ± 2 years; 184 ± 8 cm; 79 ± 7 kg) performed pseudo-random binary sequence (PRBS) work rate (WR) changes with a semi-recumbent cycle ergometer (30 and 80 W) and an arm cranking exercise device (20 and 50 W); followed by step-wise increases in WR (UpBody: 20 W · 5 min-1; LoBody: 50 W · 5 min-1).V'O2pulm was measured breath-by-breath and HR beat-to-beat. V'O2musc was estimated by the approach of Hoffmann et al. (2013), accounting for circulatory distortions. Time constants (τ) for HR (τHR), V'O2pulm (τV'O2pulm) and V'O2musc (τV'O2musc) were estimated during the PRBS phases by time-series analysis.Results: Peak oxygen uptake differed significantly between UpBody (37.8 ± 5.0 mL · min-1 · kg-1) and LoBody exercise (56.1 ± 7.4 mL · min-1 · kg-1; p<0.001). Significant differences were observed for τV'O2musc (UpBody: 41.1 ± 11.3s vs. LoBody: 29.5 ± 5.2 s; p<0.05), but not for τV'O2pulm (49.1 ± 17.1s vs. 39.6 ± 11.2 s; p>0.05) and τHR (29.1 ± 15.6s vs. 25.6 ± 8.0 s; p>0.05). Conclusions: Meaningful dissociations between V'O2pulm and V'O2musc kinetics exist for both UpBody and LoBody exercise during rapid work rate changes. Therefore, isolated V'O2pulm kinetic estimations without the consideration of the circulatory distortions may not allow a reliable assessment of V'O2musc kinetics.
ZeitschriftEuropean journal of applied physiology
Seiten (von - bis) 1665–1672
PublikationsstatusVeröffentlicht - 2015