Table 2.

Resting oxygen consumption (V̇_O2), gas exchange ratio (R), pulmonary ventilation (V̇_E), heart rate (HR) and arterial oxygen saturation (S_aO2) of 2nd generation Tibetan lowlanders (Tib 2), altitude Sherpas (Sh) untrained (UT) and trained (T) Caucasians in control conditions (PRE) and throughout altitude exposure (ALT1, ALT2, ALT3 and ALT3-O₂)

		Tibetans (Tib 2)	Sherpas (Sh)	Caucasians (UT)	Caucasians (T)
V̇O2 (ml kg−1 min−1)	PRE	4.3 ± 0.7	5.2 ± 0.9	3.7 ± 0.4§	4.3 ± 0.4
	ALT1	4.6 ± 0.5	—	4.2 ± 0.9	4.5 ± 1.3
	ALT2	4.5 ± 0.5	—	3.9 ± 0.5	4.1 ± 1.1
	ALT3	5.4 ± 0.6a	5.1 ± 1.0	4.4 ± 0.8	4.5 ± 0.6
	ALT3-O2	5.3 ± 1.0a	—	—	—
R	PRE	0.99 ± 0.07	0.94 ± 0.05	0.84 ± 0.12*	0.79 ± 0.10*§
	ALT1	0.91 ± 0.15	—	0.83 ± 0.13	0.86 ± 0.16
	ALT2	0.98 ± 0.08	—	0.91 ± 0.12	0.98 ± 0.19
	ALT3	1.02 ± 0.09	0.98 ± 0.06	0.84 ± 0.12*§	0.88 ± 0.08
	ALT3-O2	0.75 ± 0.12abcd	—	—	—
V̇E (l min−1)	PRE	12.8 ± 1.4	13.5 ± 2.0	9.2 ± 1.2*§	8.2 ± 1.8*§
	ALT1	15.5 ± 2.8a	—	17.3 ± 7.6a	14.4 ± 3.7a
	ALT2	15.7 ± 2.5a	—	16.7 ± 3.0a	15.2 ± 2.9a
	ALT3	18.3 ± 1.2abc	15.3 ± 3.2	16.4 ± 3.7a	14.2 ± 3.1a
	ALT3-O2	16.0 ± 3.0a	—	—	—
HR (beats min−1)	PRE	81 ± 12	70 ± 12	78 ± 12	58 ± 3*†
	ALT1	95 ± 16	—	92 ± 10a	80 ± 19
	ALT2	105 ± 9a	—	87 ± 6*	78 ± 8*
	ALT3	93 ± 8	87 ± 9a	96 ± 13a	79 ± 12
	ALT3-O2	92 ± 10	—	—	—
SaO2 (%)	PRE	97.5 ± 1.1	97.9 ± 0.9	97.3 ± 1.5	96.5 ± 0.7
	ALT1	89.1 ± 2.5a	—	82.5 ± 7.5a	84.1 ± 5.0a
	ALT2	91.0 ± 2.2a	—	84.4 ± 6.2a	85.9 ± 4.7
	ALT3	91.6 ± 3.5a	89.0 ± 3.0a	84.6 ± 5.0*a	84.0 ± 3.6*a
	ALT3-O2	97.6 ± 1.2bcd	—	—	—

^*Values are means ±s.d. Significantly different from Tib 2,

^§Values are means ±s.d. Significantly different from Sh

^†Values are means ±s.d. Significantly different from UT.

^aSignificantly different from PRE

^bSignificantly different from ALT1

^cSignificantly different from ALT2

^dSignificantly different from ALT3.