Pulmonary oxygen uptake and muscle deoxygenation kinetics during heavy intensity cycling exercise in patients with emphysema and idiopathic pulmonary fibrosis

Table 3 Pulmonary \( \overset{.}{V} \) O₂, HR and [HHb] responses during heavy intensity exercise according to participant condition

	Healthy	Emphysema	IPF
Baseline \( \overset{.}{V} \) O₂	0.62 ± 0.9	0.60 ± 0.12	0.75 ± 0.18
\( \overset{.}{V} \) O₂ Amp (l · min⁻¹)	1.48 ± 0.54	0.40 ± 0.11^a	0.41 ± 0.14^a
\( \overset{.}{V} \) O₂ TD (s)	15 ± 5	11 ± 7	11 ± 7
\( \overset{.}{V} \) O₂ τ (s)	31 ± 7	65 ± 11^a	69 ± 7^a
\( \overset{.}{V} \) O₂ MRT (s)	52 ± 12	81 ± 18^a	92 ± 19^a
\( \overset{.}{V} \) O₂ SC Amp (l · min⁻¹)	0.19 ± 0.10	0.01 ± 0.01^a	0.01 ± 0.01^a
\( \overset{.}{V} \) O₂ SC Amp (% EE \( \overset{.}{V} \) O₂)	7 ± 3	1 ± 1^a	1 ± 1^a
HR Amp (beats · min⁻¹)	58 ± 11	22 ± 10^a	21 ± 10^a
HR τ (s)	36 ± 12	119 ± 20^a	87 ± 19^ab
[HHb] TD (s)	NA	18 ± 9	15 ± 2
[HHb] τ (s)	NA	51 ± 23	35 ± 29
[HHb] τ’ (s)	NA	69 ± 15	54 ± 35
[HHb]: \( \overset{.}{V} \) O₂ ratio	NA	1.07 ± 0.14	1.21 ± 0.07
Work rate (W)	155 ± 56	37 ± 12	64 ± 9

Mean ± S.D. (95% confidence intervals). \( \overset{.}{V} \) O₂, oxygen uptake; Amp: Amplitude; TD: time delay; τ: phase II time constant; MRT: mean response time; SC: slow component; EE: end exercise; HR: heart rate; NA: data not available
^aSignificant difference relative to healthy participants (P < 0.05); ^bSignificant difference between patients with Emphysema and IPF (P < 0.05)

ISSN: 1471-2466