Table 2.

Blood gas variables during exercise with and without β 1 + 2 adrenergic blockade

		Exercise
	Rest	60 W	120 W	180 W	210 W	240 W	Recovery
CO2 (mm)
Control	a	9.0 ± 0.3	8.9 ± 0.6	9.2 ± 0.6	9.4 ± 0.8	9.6 ± 0.8*	9.7 ± 0.8*	8.9 ± 0.6
	v	5.5 ± 0.6	6.1 ± 0.6	6.2 ± 0.6	6.1 ± 0.8	5.4 ± 1.1	5.4 ± 0.8	5.2 ± 0.8
Propranolol	a	8.9 ± 0.6	8.9 ± 0.6	9.2 ± 0.8	9.5 ± 0.6*	9.8 ± 0.6*	—	8.8 ± 0.6
	v	5.5 ± 0.8	5.8 ± 0.6	5.6 ± 0.6	5.5 ± 0.8	5.5 ± 0.8	—	5.3 ± 0.8
(%)
Control	a	98.3 ± 0.6	98 ± 0.8	97.5 ± 0.6	97.1 ± 0.8	96.9 ± 0.6	96.8 ± 1.1*	96.7 ± 1.7*
	v	66.0 ± 4.5	65.7 ± 2.8	65.8 ± 3.9	58.6 ± 7.4	57.4 ± 7.4*	53.3 ± 8.5*	55.6 ± 5.7*
Propranolol	a	98.0 ± 0.8	97.7 ± 0.8	97.7 ± 0.8	97.5 ± 0.6	97.6 ± 1.1	—	97.2 ± 1.7
	v	60.5 ± 6.8	63.2 ± 5.1	60.8 ± 4.5	56.7 ± 7.6	51.2 ± 8.2*	—	59.4 ± 7.6
Hb (mm)
Control	a	8.7 ± 0.6	9.0 ± 0.6*	9.4 ± 0.6*	9.6 ± 0.8*	9.9 ± 0.8*	10.0 ± 0.8*	9.2 ± 0.6*
	v	8.8 ± 0.6	9.1 ± 0.6	9.4 ± 0.6	9.8 ± 0.8	9.3 ± 1.7	10.0 ± 0.6	9.2 ± 0.6
Propranolol	a	8.8 ± 0.8	9.0 ± 0.6*	9.3 ± 0.6*	9.7 ± 0.6*	9.7 ± 0.6*	—	9.0 ± 0.6*
	v	8.8 ± 0.6	9.1 ± 0.6	9.4 ± 0.6*	9.8 ± 0.6*	9.8 ± 0.6*	—	9.1 ± 0.6*
(kPa)
Control	a	13.4 ± 0.8	13.2 ± 0.8	12.7 ± 0.8	13.1 ± 1.7	13.1 ± 1.1	13.3 ± 2.3	12.6 ± 1.7
	v	4.9 ± 0.3	4.9 ± 0.3	5.0 ± 0.3	4.7 ± 0.3	4.5 ± 0.3	4.5 ± 0.3*	4.4 ± 0.3*
Propranolol	a	13.1 ± 1.3	12.6 ± 0.8	12.6 ± 1.1	12.7 ± 0.6	13.0 ± 0.8	—	12.2 ± 1.9
	v	4.5 ± 0.6	4.7 ± 0.6	4.6 ± 0.3	4.5 ± 0.6	4.1 ± 0.6	—	4.6 ± 0.6
(kPa)
Control	a	5.5 ± 0.3	5.6 ± 0.3	5.5 ± 0.3	5.0 ± 0.6*	4.4 ± 0.6*	3.9 ± 0.3*	4.7 ± 0.6*
	v	7.0 ± 0.3	7.1 ± 0.3	6.9 ± 0.3	6.5 ± 0.6*	6.3 ± 0.8*	6.3 ± 0.3*	6.5 ± 0.3
Propranolol	a	5.5 ± 0.6	5.6 ± 0.3	5.5 ± 0.3	4.1 ± 0.3*	4.6 ± 0.6*	—	5.0 ± 0.6
	v	7.1 ± 0.3	7.1 ± 0.3	7.1 ± 0.3	6.8 ± 0.3	6.6 ± 0.3*	—	6.7 ± 0.3*

Blood gas variables during exercise with and without non-selective β-blockade. CO₂, CO₂ concentration; , O₂ saturation; Hb, haemoglobin concentration; , O₂ partial pressure; , carbon dioxide partial pressure.

^*Different from rest (P < 0.05);

^†different from control exercise (P < 0.05). Values are means ± s.d.