Table 4.

Mean data during rest and the constant load exercise bout (n= 18)

	Rest	1st Air	Heliox	2nd Air
(mmHg)	10 ± 1	28 ± 2§	28 ± 2§	29 ± 2§
pH	7.32 ± 0.01	7.34 ± 0.01§	7.34 ± 0.01§	7.32 ± 0.02
Toes (°C)	37.3 ± 0.1	37.6 ± 0.1§*	38.1 ± 0.1§	38.3 ± 0.1§*
K+ (mmol l−1)	3.6 ± 0.1	5.4 ± 0.1§	5.3 ± 0.1§	5.3 ± 0.1§
HCO3− (mmol l−1)	17 ± 1	19 ± 0.4§	18 ± 1§	19 ± 1§
Hb (g dl−1)	12.5 ± 0.2	13.1 ± 0.2§	13.2 ± 0.2§	13.3 ± 0.2§
VT (l)	0.7 ± 0.03	1.8 ± 0.1§	1.9 ± 0.1§	1.9 ± 0.1§
f (beats min-1)	17 ± 1	40 ± 2§*	48 ± 3§	47 ± 3§
(l min−1)	0.32 ± 0.01	2.6 ± 0.1§*	2.9 ± 0.1§	2.9 ± 0.1§
(l min−1)	0.26 ± 0.01	2.3 ± 0.1§*	2.7 ± 0.1§	2.8 ± 0.1§
RER	0.81 ± 0.02	0.87 ± 0.01§*	0.94 ± 0.01§	0.97 ± 0.02§
VD/VT	0.2 ± 0.01	0.14 ± 0.01§	0.16 ± 0.01§	0.17 ± 0.01
Ti (%)	33 ± 1	48 ± 1§	48 ± 1§	47 ± 1§
WOBel (%total)	69 ± 2	55 ± 2§*	60 ± 2§	51 ± 2§*
WOBres (%total)	31 ± 2	45 ± 2§*	40 ± 2§	49 ± 2§*

Values are mean ± SEM. , alveolar oxygen tension; , alveolar-to-arterial oxygen difference; T_oes, oesophageal temperature; Hb, haemoglobin; V_T, tidal volume; f, breathing frequency; , oxygen consumption; , carbon dioxide production; RER, respiratory exchange ratio; V_D, physiological deadspace; T_i, inspiratory time; V_T, tidal volume; WOB_el, elastic work of breathing; WOB_Res, resistive work of breathing. §Different from rest; *different from heliox, P < 0.05.