. 2020 Nov 16;105(12):2123–2140. doi: 10.1113/EP089070

TABLE 1.

Mean (95% CI) cardiorespiratory responses obtained during the three successive cold‐water (20°C) immersions (CWI_A: 1st trial, CWI_B: 2nd trial, CWI_C: 3rd trial) performed in normoxia and hypoxia

	Normoxia ( $P_{O_{2}}$ : 21 kPa)			Hypoxia ( $P_{O_{2}}$ : 12 kPa)
	CWI_A	CWI_B	CWI_C	CWI_A	CWI_B	CWI_C
${\dot{V}}_{O_{2}}$ (l min⁻¹)	0.60 (0.09)	0.63 (0.07)	0.62 (0.08)	0.64 (0.07)	0.73 (0.07) ^*	0.79 (0.09) ^†‡*
${\dot{V}}_{O_{2}}$ (l min⁻¹) during CWI_L‐60	0.64 (0.09)	0.62 (0.06)	0.62 (0.08)	0.67 (0.09)	0.72 (0.11) ^*	0.77 (0.11) ^†*
%Shiv_peak during CWI_L‐60	45 (8)	43 (7)	44 (8)	47 (8)	51 (11) ^*	55 (12) ^†*
EE (kcal)	350 (52)	353 (41)	338 (38)	357 (38)	393 (43)	420 (57) ^*
${\dot{V}}_{C O_{2}}$ (l min⁻¹)	0.50 (0.07)	0.52 (0.06)	0.49 (0.05)	0.53 (0.06)	0.58 (0.06) ^*	0.62 (0.07) ^†‡*
RER during CWI_L‐60	0.81 (0.03)	0.79 (0.02) ^#	0.78 (0.03) ^†	0.83 (0.02)	0.80 (0.02)#	0.79 (0.02) ^†
${\dot{V}}_{E}$ (l min⁻¹)	14.2 (1.9)	15.0 (2.3)	14.0 (1.4)	16.5 (2.0) ^*	19.9 (2.5) ^#*	21.5 (2.3) ^†‡*
V _T (l)	1.23 (0.17)	1.26 (0.14)	1.09 (0.13)	1.34 (0.20) ^*	1.48 (0.17) ^*	1.54 (0.25) ^*
f _R (breaths min⁻¹)	12 (2)	13 (3)	14 (2)	13 (3)	14 (3)	15 (2) ^†
$P_{ETC O_{2}}$ (mmHg)	37.5 (2.2)	37.2 (1.9)	37.1 (1.3)	33.7 (1.3) ^*	31.2 (1.4) ^#*	30.5 (1.4) ^†*
SAP (mmHg)	129 (3)	121 (5) ^#	122 (6) ^†	130 (5)	124 (10) ^#	125 (7) ^†
DAP (mmHg)	77 (3)	71 (4) ^#	74 (5)	78 (3)	74 (3) ^#	75 (3)

Significant difference # between CWI_A and CWI_B, † between CWI_A and CWI_C, ‡ between CWI_B and CWI_C, and * between normoxic and hypoxic trial (P ≤ 0.05). CWI_L‐60, the last 60 min of each cold‐water immersion; DAP, diastolic arterial pressures; EE, energy expenditure; f _R, respiratory frequency; $P_{ETC O_{2}}$ , partial pressure of end‐tidal carbon dioxide; RER, respiratory exchange ratio; Inline graphic SAP, systolic arterial pressures; ${\dot{V}}_{C O_{2}}$ carbon dioxide production; V _T, tidal volume; ${\dot{V}}_{E}$ , expired ventilation; ${\dot{V}}_{O_{2}}$ , oxygen uptake; %Shiv_peak, estimated peak shivering metabolic rate.