Table 2 Effects of proportional assisted ventilation (PAV) and sham ventilation on oxygen transport/utilisation variables at isotime (the shortest test between the two experimental conditions in a given subject) and at exercise cessation (Tlim) (N = 16)

Variables	At isotime		At Tlim
Variables	Sham ventilation	PAV	Sham ventilation	PAV
Cardiovascular/haemodynamics
Cardiac output
Absolute (l/min)	12.8 (2.5)	13.0 (3.0)	12.9 (2.5)	13.0 (2.8)
Δ exercise–rest (l/min)	6.5 (2.6)	6.8 (2.8)	6.6 (2.5)	6.9 (2.5)
Stroke volume
Absolute (ml)	88 (20)	93 (18)	97 (15)	95 (15)
Δ exercise–rest (ml)	18 (13)	20 (14)	22 (12)	22 (15)
Heart rate
Absolute (bpm)	134 (18)	133 (20)	136 (19)	139 (18)
Δ exercise–rest (bpm)	53 (23)	50 (20)	54 (22)	57 (19)
Oxygen pulse
Absolute (ml/min/beat)	8.2 (2.0)	8.3 (2.0)	8.2 (1.9)	8.2 (2.0)
Systemic oxygenation
Spo₂
Absolute (%)	90.4 (3.8)	92.3 (1.1)	89.3 (3.6)	90.6 (4.9)
Δ exercise–rest	−4.6 (3.4)	−3.7 (4.4)	−5.7 (3.7)	−5.4 (4.9)
Cao₂est (ml%)
Absolute	18.7 (4.5)	18.2 (3.9)	18.1 (3.6)	18.8 (4.1)
Δ exercise–rest	−2.4 (0.3)	−2.5 (0.6)	−2.3 (0.8)	−2.7 (0.7)
Do₂est (l/min)
Absolute	2.8 (0.4)	2.7 (0.5)	2.5 (0.4)	2.4 (0.3)
Δ exercise–rest	1.9 (0.2)	2.0 (0.3)	1.9 (0.2)	1.8 (0.5)
Leg muscle oxygenation
Δ[HHb] (% MVC)	88.7 (15.4)	72.9 (16.4)*	90.7 (14.1)	71.8 (15.9)*
Δ[O₂Hb] (% MVC)	−85.4 (19.4)	−70.4 (18.8)*	−87.7 (18.7)	−69.3 (19.4)*
Δ[Hb_tot] (% recovery)	58.3 (10.9)	74.3 (16.5)*	58.4 (12.3)	77.6 (17.1)*
TOI (%)	35.7 (17.1)	48.7 (18.7)*	34.3 (16.7)	50.2 (19.0)*
Blood lactate
Absolute (μmol/l)	–	–	3.8 (1.3)	3.9 (1.2)
Lactate/time (μmol/l/min)	–	–	0.99 (0.40)	0.85 (0.35)*

Values are mean (SD).
*p<0.05 (paired t test for between-group differences at a given time point).
Cao₂est, estimated arterial oxygen content; Do₂est, estimated oxygen delivery; HHb, reduced haemoglobin; Hb_tot, total haemoglobin; MVC, maximum voluntary contraction; O₂Hb, oxyhaemoglobin; Spo₂, oxyhaemoglobin saturation by pulse oximetry; TOI, tissue oxygenation index.