. Author manuscript; available in PMC: 2023 Aug 1.

Published in final edited form as: J Physiol. 2022 Jul 7;600(16):3671–3688. doi: 10.1113/JP283051

Table 3.

Pulmonary gas exchange and cardiorespiratory responses to normoxia and hyperoxic hypercapnia at rest and during passive leg movement (LM) in men

	Normoxia		Hyperoxic hypercapnia		p value

	Rest	LM	Rest	LM	Main effect of LM	Main effect of hypercapnia	Interaction effect
Pulmonary gas exchange
S_pO₂ (%)	97 ± 2	97 ± 2	100 ± 1^†	100 ± 0^†	0.099	<0.001	0.364
P_ETO₂ (mmHg)	85 ± 5	81 ± 5^*	526 ± 10^†	526 ± 9^†	0.053	<0.001	0.051
P_ETCO₂ (mmHg)	33 ± 3	35 ± 3^*	45 ± 2^†	45 ± 2^†	0.001	<0.001	0.046
Ventilatory responses
V̇_E (L·min⁻¹)	11 ± 2	13 ± 3	31 ± 11^†	33 ± 9^†	0.086	<0.001	0.873
f_B (breaths·min⁻¹)	15 ± 4	18 ± 5^*	19 ± 5^†	20 ± 4	0.056	0.026	0.062
V_T (L)	0.9 ± 0.2	0.8 ± 0.1	1.7 ± 0.4^†	1.7 ± 0.3^†	0.595	<0.001	0.065
Hemodynamic responses
MAP (mmHg)	101 ± 15	97 ± 18^*	107 ± 17^†	102 ± 15^*^†	0.020	0.002	0.992
HR (beats·min⁻¹)	67 ± 9	77 ± 13^*	69 ± 11	79 ± 9^*	0.001	0.154	1.000
SV (mL)	78 ± 12	90 ± 14^*	84 ± 18^†	97 ± 18^*^†	<0.001	0.025	0.484
CO (L·min⁻¹)	5.2 ± 0.7	6.6 ± 1.4^*	5.7 ± 1.0^†	7.1 ± 1.3^*^†	<0.001	0.021	0.934
LBF (L·min⁻¹)	0.3 ± 0.1	1.6 ± 0.4^*	0.3 ± 0.1	1.5 ± 0.4^*^†	<0.001	0.244	0.080
LVC (mL·min⁻¹·mmHg)	2.8 ± 0.9	16.4 ± 5.8^*	3.0 ± 0.8	14.4 ± 5.8^*^†	<0.001	0.063	0.023

S_pO₂: oxyhemoglobin saturation; P_ETO₂: end-tidal partial pressure of O₂; P_ETCO₂: end-tidal partial pressure of CO₂; V̇_E: minute ventilation; f_B: breathing frequency; V_T: tidal volume; MAP: mean arterial pressure; HR: heart rate; SV: stroke volume; CO: cardiac output; LBF: leg blood flow; LVC: leg vascular conductance.

p < 0.05 vs. rest;

^†

p < 0.05 vs. normoxia. Pulmonary gas exchange and ventilatory responses are 60-s average at rest and during LM, while hemodynamic responses are 60-s average at rest and the maximal response during LM; n = 12. Data were analyzed using two-way repeated-measure ANOVA with Tukey’s post hoc test and are presented as mean ± S.D.